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Garage => Mechanicals => Topic started by: McNuggets on 16 August 2020, 06:23 PM

Title: Restoration of 6.9 #496
Post by: McNuggets on 16 August 2020, 06:23 PM
Hello everyone,

I'm a mechanical engineer from New York, recently moved to California. I've been enamored with Mercedes cars for as long as I can remember, and have many pleasant memories of riding around on the rear bench of my father's 350SL, and of learning to drive in the mighty 560SEL. A few weeks ago I bought my first project car, naturally choosing a 6.9 as a good starting place for the beginner ;D. The details (and photos) in the listing were pretty sketchy, but from what I have seen on the car and the documentation that came with it, this was an early Euro spec model imported through Houston in 1986 as a grey market car. It was driven by an electrical engineer here in the SF bay area until 2002 when the seller bought it from a scrap yard. He failed to get it running, and after purchasing a new engine and transmission (??), he..... let it sit, for 18 years, until I bought it. I haven't registered it with the DMV yet (and am now far removed from the ten day window in which I was supposed to, oops) so I cannot get the data card from the classic center yet, but I am very interested in obtaining it. The title lists the model year as 1900, the import documentation lists 1976 and 1977, and the data plate near the radiator bears the leading digit "5." If it is a 1975 model, having proof will come in handy as the car would otherwise need to pass smog in California, which means I would need to restore the aftermarket closed-loop lambda control system retrofitted by the importer, to working condition.

The car is in pretty rough shape overall. The interior is totally dried out and crackles painfully when disturbed, the paint is sunblasted and there is some rust over the driver's door where a vinyl top once trapped rainwater, and there is forklift damage to the side skirts, floor pans, and trunk pan, but I believe the car was originally totalled by a failure in the fuel distributor. My thinking is based on the following facts:
1.) The airflow meter plate moves freely and does not feel like it is touching the control plunger at all.
2.) The car came with the fuel tank in the back seat, having been replaced by a red jerry can in the trunk.
3.) Removal of the valve covers brought forth the hideous stench of old gas.
4.) The engine, I was told by the seller, would turn over with the starter but not stay running.
Based on this I was pretty sure previous owner had flooded it while trying to fix something fuel related, and my attention turned to determining whether it had any bent rods, having recently finished a reading of Raueda1's horror story of an experience with a maladjusted fuel distributor last summer. What I have done so far is this:
0.) Bought missing 6.9 emblem on ebay as a good luck charm.
1.) Borescope inspection of cylinders via spark plug hole revealed the pistons were generally dirty and looked as though the engine had been running very rich, although some had VERY clean areas where fuel had pooled, dissolved these deposits, and evaporated.
2.) I sprayed PB blaster into the cylinders, and blew them out with compressed air to be sure there was no solid debris lurking
3.) I turned the engine over with a breaker bar and 50mm socket at the crank pulley, for two laps of the timing chain and found no problems
4.) I tuned the engine over with a new battery, and measured compression. The workshop manual says to do this with a warm engine but that's not really an option for me. Overall, readings looked good. In Bar and in order 1-8 they measured 10.5, 11.5, 10, 11.5, 11.5, 9.5, 10, 10. Cylinder 6 is a bit low, but the gauge I used was rented from O'Reilly's and was coming unscrewed all the time. Minimum spec is 8.5 Bar, and all cylinders should be within 1.5 Bar of each other. The camshafts are mostly clean, and the oiler tubes are at least dribbling oil onto each lobe (I replaced the oil, but did not bleed air out as the manual suggests, as the engine does not run yet). I feel good enough about this result to proceed, which brings me to today.

What do I do now, w116.org? I am planning to remove the retrofitted lambda control system until I can get the car running. I've ordered a rebuild kit for the FD as well as the WUR, and plan to get these components working on the bench before shelling out for new injectors and trying to start the engine for real. There is a lot to do, and I've already written a wall of text in this post. I plan to update this thread as I make progress over the next few months or years. I look forward to writing back and forth to you all, and to learn as much as I can about these cars, as we appreciate an excellent series of top-class autobahn cruisers together!

- Nuggies
Title: Re: Restoration of 6.9 #496
Post by: john erbe on 16 August 2020, 08:37 PM
Good luck with project. Im up here in Vallejo. May be able to help out with some extra parts Ive got laying around. PM me if interested.
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 16 August 2020, 11:15 PM
Welcome to the house of fun ;D  Indeed here you will find a lot of help, if not a place to come and cry in your beer every now and then 8)

Yes KJET needs super clean fuel to be happy, so the fact that there has been some shenanigans in the fuel system by the previous owner apparently is not a good sign.  If the car sat for a long time and the guy/gal tried to start it with a gunked up fuel system then you will need to clean it out properly.  Sounds like you are on this path already, so, carry on ;)

Fresh oil is a must yes, also the fact that you are getting oil to the top end with cranking bodes well too.  The bottom end of these engines is hella stout, so a bent rod is unlikely I would say, but of course not impossible as Dave (raueda1) found out...

You can also run a quart of ATF in a full tank of gas as a detergent, many folks do this routinely to keep the fuel system happy.

You will likely need to overhaul the shock mounted fuel delivery package at the back of the car too.  All those parts are still readily available and cheap (ish).  Change all the hoses too, this is an area ripe for a Car - B - Q :o

Cheers and good luck!  Also post some pics of this bad boy ;)
Title: Re: Restoration of 6.9 #496
Post by: rumb on 17 August 2020, 08:29 AM
Welcome,  Your tale sounds familiar probably not too different than mine, including the forklift damages.   Sounds like you are on the right track getting the fuel system cleaned out and rebuilt first.

What is the VIN, you can then calculate the year of mfg.  MB of that vintage were often titled the year first sold. The datacard will have the actual birth date on it. Edit: 496 was the 22nd car built in 1976.

Post photos! including the lamba system as I have not ever seen an aftermarket one on a 6.9.  Most often they have EGR system added for EPA.

Check out Federal emissions exemptions. Here in Colo that then allowed state exemption. 

https://www.epa.gov/sites/production/files/2020-07/documents/form3520-1-2020-07-secured-enabled.pdf

Code E, vehicle older than 21 years old will original equipment. (you would want to remove all mods to meet this.)
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 17 August 2020, 10:39 AM
Welcome, welcome, sounds like you got a fun little project going!  Sitting 18 years isn't kind to the car and ensures that things are stuck with varnish, gum, sediment, etc etc.  You can safely assume that things are stuck, blocked, etc.

For sure, renew all the rubber bits on the tank and rear fuel module.  Absolutely essential.  I'd take out the tank, replace the tank sieve and clean that out too while things are disconnected.  Otherwise you'll have fuel delivery gremlins forever.  You might as well just replace the injectors too.  They aren't very expensive and new ones will just remove another source of problems.  As for FD and WUR, sounds like you know you'll need a pressure gauge kit.  I wouldn't even bother trying to start the car till they're rebuilt and you're confident that the pressures are right.  Get a primary pressure regulator rebuild kit too.  It will include the teeny washers for setting primary pressure among other things.  PM me if you're doing the FD rebuild yourself, I have some useful info on that.  Finally, inspect all the rubber air and vacuum hoses and fittings carefully.  If they're stiff just replace.  Vacuum leaks wil cause all kinds of undiagnosable problems and drive you crazy.

The old M100 board has an excellent Bosch K-jet diagnosis manual.  It's super, super helpful.  It would be great to add to the tech docs list here but I don't know how and it's too big to email.  Anyway, if you can get your hands on that it goes through all the steps of getting the fuel system working right.

Good luck!  Take your time and enjoy it.  We'll enjoy hearing about it as much as you enjoy doing it, so keep posting.  Cheers,
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 17 August 2020, 04:55 PM
Another topic you need to address would be coolant of course.  I would also just go ahead and change the thermostat as well.

Do not try and drain the block via the drain plugs at this point.  Just drain the radiator, expansion tank and the hoses as much as you can.  Then fill with Zerex G-05 Coolant (Valvoline) diluted 50/50 with distilled water.  The 6.9 water pump needs to be a babied  as much as you can and coolant changes are cheap insurance, they are pricey and hard to change out, so preventative maintenance is key.

Cheers
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 17 August 2020, 06:48 PM
Quote from: daantjie on 17 August 2020, 04:55 PM
Another topic you need to address would be coolant of course.  I would also just go ahead and change the thermostat as well.

Do not try and drain the block via the drain plugs at this point.  Just drain the radiator, expansion tank and the hoses as much as you can.  Then fill with Zerex G-05 Coolant (Valvoline) diluted 50/50 with distilled water.  The 6.9 water pump needs to be a babied  as much as you can and coolant changes are cheap insurance, they are pricey and hard to change out, so preventative maintenance is key.

Cheers
Yeah, great point.  FWIW, I had my radiator flushed/boiled out.  The shop did a flow test and said that it was about 30% blocked by deposits!  I wasn't having overheating problems but it runs cooler now and the system holds the temp much better.
Title: Re: Restoration of 6.9 #496
Post by: Jed on 17 August 2020, 09:51 PM
Pictures Please!

Inside and out!
Title: Re: Restoration of 6.9 #496
Post by: Randys01 on 18 August 2020, 03:55 AM
Welcome to Looney Tunes. ;D
...at last you will be pitting all your engineering skills against the dark forces..........lol!!
...........good luck......make sure you exhaust the Tech info/search function to bring yourself up to speed.

You will find different folk on this site have different "sweet spot" knowledge.  Between the lot of us,  we could get a Renault 750 sorted?!! :o
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 22 August 2020, 11:48 PM
I wrote out a longer summary of the car's status but one of the photos I attached was too small, and the page deleted what I had written :( Anyway, some of you had asked for pictures of the car and right now what photos I have are in a jumbled heap in google drive, in apple's silly .HEIC format. I've attached a few small photos to this post, and will try to get hold of a small digital camera for the future.

While waiting for FD and WUR rebuild kits to arrive, I removed them from the car, along with the 8 injector lines and the airflow meter. I set about looking at some of the vacuum connections on top of the engine, and decided I should replace or cap off as many as possible until I have a running engine. To that end, I've ordered 8 new injectors, 8 injector seals, the two U-shaped rubber hoses at the idle air control valve, the rubber seal between the airflow meter and throttle body, and the vacuum tubes between the WUR, ignition distributor, and intake manifold. I would like to remove the intake manifold entirely as it would allow me to clean the intake manifold, plenum, throttle body, and the inside of the vee, but doing so would mean needing to replace the eight rubber seals between the underside of the intake manifold and the plenum. For the 117 engines, genuine MB parts are available for about $8 each. EPC shows a different part number for the M100, 100-140-04-65, which I've found only in one or two places and which costs $70 each. Has anyone tried fitting the M117 seals to the M100? The photos look identical, but I cannot be sure of the diameter and I cannot compare a M117 seal to what's on the car without committing to this, or spending $70 on a single rubber seal. There's also the question of the intake manifold gaskets: can these be reused? I've found a complete set of NOS asbestos gaskets for 50 Euro, but I'd rather leave it all alone if the rubber parts are not known to leak air commonly, and if I need to spend hours scraping asbestos gaskets to do the job.

There's also a rubber Y hose that leads from the idle air control valve to the two cylinder banks. On the 4.5, I think this is P/N 116-090-01-82 but on the 6.9 the shape and orientation is slightly different. I can't find it in EPC, and the P/N molded into it (100-090-00-82?) brings up nothing in internet search. Does anyone know where this hose can be found? Mine is rock-hard and I want to replace it.

In one of the below pictures (I hope), you can see a piece of yellow plastic at the right of the FD. This is an extra fuel injector, which dumps fuel from the WUR control pressure port into the FD return port, allowing an ECU (which I've still not been able to find) to fine-tune the control pressure similarly to KE-Jet. There's also a Purolator brand charcoal canister haphazardly hose-clamped in place, which I want to replace with the boxy OEM style canister, if it will fit.
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 23 August 2020, 09:56 AM
Moving along!  Plenty to comment on.  But first, a point of clarity - is this a Euro car that was federalized more-or-less when imported?  If so I'd just get rid of all the USA smog stuff, whatever it is, and return to unmodified euro status.  Are there state regs preventing you from doing so?  This will make life a lot simpler.  Anyway, see bold insertions.

Quote from: McNuggets on 22 August 2020, 11:48 PM
I wrote out a longer summary of the car's status but one of the photos I attached was too small, and the page deleted what I had written :( Anyway, some of you had asked for pictures of the car and right now what photos I have are in a jumbled heap in google drive, in apple's silly .HEIC format. I've attached a few small photos to this post, and will try to get hold of a small digital camera for the future.  Yes!  Pics are so helpful!

While waiting for FD and WUR rebuild kits to arrive,
PM or email me on FD rebuild.  The kit instructions (if any) are entirely inadequate.  Also, it's still far in the future, but you'll need to pick up a fuel pressure gauge kit if you don't have that already.

I removed them from the car, along with the 8 injector lines and the airflow meter. I set about looking at some of the vacuum connections on top of the engine, and decided I should replace or cap off as many as possible until I have a running engine.
This plays to the smog question.  All the vacuum connections do something - if they're capped off you won't have a running engine, or at least not a properly running engine.  Sooner or later they'll all need to be right.

To that end, I've ordered 8 new injectors, 8 injector seals, the two U-shaped rubber hoses at the idle air control valve, the rubber seal between the airflow meter and throttle body, and the vacuum tubes between the WUR, ignition distributor, and intake manifold. I would like to remove the intake manifold entirely as it would allow me to clean the intake manifold, plenum, throttle body, and the inside of the vee, but doing so would mean needing to replace the eight rubber seals between the underside of the intake manifold and the plenum. For the 117 engines, genuine MB parts are available for about $8 each. EPC shows a different part number for the M100, 100-140-04-65, which I've found only in one or two places and which costs $70 each. Has anyone tried fitting the M117 seals to the M100? The photos look identical, but I cannot be sure of the diameter and I cannot compare a M117 seal to what's on the car without committing to this, or spending $70 on a single rubber seal.
I tried and can confirm that they are not the same.  The M100 seals are indeed bigger.  But to my surprise mine weren't bad.  Yours may be OK too.  If you take it apart you'll be able to easily see how well they seal.  It's not at all impossible that they'll be OK.

There's also the question of the intake manifold gaskets: can these be reused? I've found a complete set of NOS asbestos gaskets for 50 Euro, but I'd rather leave it all alone if the rubber parts are not known to leak air commonly, and if I need to spend hours scraping asbestos gaskets to do the job.
I doubt that they can be reused, but maybe somebody else knows better.  Mine came off perfectly clean, not like the usual head gasket mess.  But....  The Classic Center has (or had) left and right gasket kits that are pretty reasonable.  They include head gasket, intake manifold gasket, valve cover gasket and other odds and ends (can't recall exactly what).  Email them, very very worthwhile.

There's also a rubber Y hose that leads from the idle air control valve to the two cylinder banks. On the 4.5, I think this is P/N 116-090-01-82 but on the 6.9 the shape and orientation is slightly different. I can't find it in EPC, and the P/N molded into it (100-090-00-82?) brings up nothing in internet search. Does anyone know where this hose can be found? Mine is rock-hard and I want to replace it.
Can't help with this at the moment.  :(

In one of the below pictures (I hope), you can see a piece of yellow plastic at the right of the FD. This is an extra fuel injector, which dumps fuel from the WUR control pressure port into the FD return port, allowing an ECU (which I've still not been able to find) to fine-tune the control pressure similarly to KE-Jet. There's also a Purolator brand charcoal canister haphazardly hose-clamped in place, which I want to replace with the boxy OEM style canister, if it will fit.
I've never seen that yellow thing before.  For sure, it's absolutely not something on a stock Euro engine.  Nor is there any kind of ECU whatsoever, at least on euro engines.  I'd dump all that stuff and return to stock.  Also, USA heads have a couple vacuum fittings, not sure where they go.  The euro heads don't have any such fittings and the casting has plugs instead.  It might be helpful to confirm that you've got euro heads.  Maybe others can comment further.
BTW, you seem to be digging into the whole thing here, which is certainly the right way IMO.  Out of laziness I kind of learned that the hard way.  Doing it piecemeal you can go nuts chasing issues.   Cheers,
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 23 August 2020, 10:57 AM
Another thought just occurred to me.  Should you decide to take off the intake manifold, there are a couple bolts that are close to or connected to the cooling passages.  Apparently these often freeze, as mine did, and so naturally the head shears off.  Now you've got a loose manifold that's impossible to remove cause there's still 10mm of bolt shaft sticking into the manifold preventing it from being lifted off.  Drilling it out is pretty ugly.  Lesson:  psychologically prepare yourself and be ready to deal with it if it happens.
Title: Re: Restoration of 6.9 #496
Post by: Alec300SD on 23 August 2020, 11:49 AM
Quote from: McNuggets on 22 August 2020, 11:48 PM
EPC shows a different part number for the M100, 100-140-04-65, which I've found only in one or two places and which costs $70 each. Has anyone tried fitting the M117 seals to the M100? The photos look identical, but I cannot be sure of the diameter and I cannot compare a M117 seal to what's on the car without committing to this, or spending $70 on a single rubber seal.
Lst price is $70, but you save a bit at online MB dealership parts webstores.
I've used mboemparts.com, shipping is reduced with promo code BENZWORLD2017.
https://www.mboemparts.com/oem-parts/mercedes-benz-connector-intake-manifold-1001400465


Quote from: McNuggets on 22 August 2020, 11:48 PM
There's also a rubber Y hose that leads from the idle air control valve to the two cylinder banks. On the 4.5, I think this is P/N 116-090-01-82 but on the 6.9 the shape and orientation is slightly different. I can't find it in EPC, and the P/N molded into it (100-090-00-82?) brings up nothing in internet search. Does anyone know where this hose can be found? Mine is rock-hard and I want to replace it.

Adding the letter A can help in  parts searches.
A 100 090 00 82 shows up on the Russian EPC  as PANTS (between item 258 and item 265) but has been replaced by two parts: A 100 090 01 82
• +001 A 100 094 04 41.

Unfortunately, A 100 090 01 82 is a discontinued part as well.
A 100 094 04 41 has been superceeded by part number A 116 094 07 41.
A 116 094 07 41 is stlll available.

MB does remaufacture NLA parts if there is adequate demand:
http://www.peachparts.com/shopforum/4067363-post34.html


Title: Re: Restoration of 6.9 #496
Post by: PosedgeClk on 23 August 2020, 06:33 PM
Quote from: raueda1 on 23 August 2020, 10:57 AM
Another thought just occurred to me.  Should you decide to take off the intake manifold, there are a couple bolts that are close to or connected to the cooling passages.  Apparently these often freeze, as mine did, and so naturally the head shears off.  Now you've got a loose manifold that's impossible to remove cause there's still 10mm of bolt shaft sticking into the manifold preventing it from being lifted off.  Drilling it out is pretty ugly.  Lesson:  psychologically prepare yourself and be ready to deal with it if it happens.
Kroil and a torch go a long way.
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 24 August 2020, 07:46 AM
Interesting to note the decal on the dash knob for height control showing the 3x settings,  I have never seen this, wonder if it's stock ???
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 24 August 2020, 09:28 AM
Quote from: daantjie on 24 August 2020, 07:46 AM
Interesting to note the decal on the dash knob for height control showing the 3x settings,  I have never seen this, wonder if it's stock ???
I noticed that too.  Not stock, I think.  My impression is that early cars had round knob, and this is an early car, to be sure.
Title: Re: Restoration of 6.9 #496
Post by: john erbe on 24 August 2020, 05:28 PM
Regarding emissions, here in CA anything manufactured after '74 has to be smog tested and at a shop that's "Star Rated". Bottom line dont take off any emissions controls.
Title: Re: Restoration of 6.9 #496
Post by: Jed on 24 August 2020, 10:17 PM
Quote from: raueda1 on 24 August 2020, 09:28 AM
Quote from: daantjie on 24 August 2020, 07:46 AM
Interesting to note the decal on the dash knob for height control showing the 3x settings,  I have never seen this, wonder if it's stock ???
I noticed that too.  Not stock, I think.  My impression is that early cars had round knob, and this is an early car, to be sure.

Yeah, never seen that sticker before either. Has anyone seen that sticker before?

.Also never seen or heard of a round knob? 
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 25 August 2020, 12:21 PM

The only round pull knobs I've seen is on the W126.
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 25 August 2020, 01:59 PM
Quote from: daantjie on 25 August 2020, 12:21 PM

The only round pull knobs I've seen is on the W126.
Here it is.  Maybe from a W126?  But there it is.  My car a few other oddities.  Rumb says the straps behind the seats are some kind of lumbar support.  Whatever they are, Ido know this:  they don't work and you practically never see them.  My WUR is also flipped 90deg so tubes are more-or-less straight, not bent.  The bottom line is that these cars seem to have been more minor variants than we'll ever know.

To OP:  sorry for steering you wrong on removing smog stuff.
Title: Re: Restoration of 6.9 #496
Post by: Jed on 25 August 2020, 05:39 PM
Very interesting dave! What is your build number? #484 which is my 76 6.9 has a square knob. Maybe they just installed whatever they had laying around in the early days!?
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 25 August 2020, 07:48 PM
Quote from: Jed on 25 August 2020, 05:39 PM
Very interesting dave! What is your build number? #484 which is my 76 6.9 has a square knob. Maybe they just installed whatever they had laying around in the early days!?
Yeah, this stuff is bizzare.  Mine is #923 - early but not as early as yours.  We'll never know!
Title: Re: Restoration of 6.9 #496
Post by: slfan on 26 August 2020, 04:18 AM

When restoring my 6.9, I thought I had lost the suspension knob and after looking-up the part number in the EPC ordered one from the Classic Center.  The one I received was also round.  Therefore, I believe this round knob is an updated replacement from the W126.
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 26 October 2020, 09:17 PM
Hi everyone, it has been a little while now and I've had a trickier time balancing this project with my day job than I wanted. I've been getting really anxious about how much is still to be done and how uncertain the state of the engine is so I did the natural thing, and rushed the job :D I disassembled the FD, freed the stuck piston, reassembled (no sealant between the halves, really cutting corners), stripped half the case screws, tested it, and it leaked like a sieve. I took it apart again, saw that I had split the lower oring on the cylinder assembly, lapped the casting halves to 3000 grit on a surface plate, reassembled with split oring still in place, stripped the rest of the case screws trying to torque them up to 70in-lbf (I got this torque spec from a third party, are proper Bosch manuals available?), tested, and it seemed to be OK. The damaged oring separates the lower chambers of the FD from a void space in the casting whichseems to be vented to the return line. No leaks as far as I could tell, but I only bench tested it for maybe a half hour. Fuel delivery for each cylinder should be tested with the injectors installed and firing into soda bottles which I had saved up, but I am impatient so I observed the eight open ports filling with fuel as I depressed the airflow meter plate and decided the variation from cylinder-to-cylinder was at least not grotesquely huge, and that that was good enough for now. One more nagging problem: system pressure drops from 5.2 bar to about 2.6 bar instantly. I'm not sure how I will tell if this is a bad check valve in my original pump, or if I screwed up the pressure regulator assembly in the FD somehow but given all the mickey-mouse things I did to the FD I wouldn't be surprised if my problem is there.

I disassembled the WUR into its pieces, including pressing out the steel fuel cell, bimetallic strip mount, and plug by the vacuum diaphragm. I am not sure whether or not I ruined a perfectly good calibration doing this, but I suspect the WUR on my car was adjusted to suit the oddball closed-loop lambda control that was installed during federalization, so I committed to re-calibrating it early on. Pressing the steel part out was a real pain, after soaking it in penetrating oil I needed to use a lighter (I don't have a torch and I live in a rental house with fire sprinklers all over the place) to heat the body and reef on the vice to move it at all. Then came reassembly. Here I again tried to cheat and simply reassemble with new seals, but I found that the control pressure was pinned at system pressure when I tried testing it. That is to say, the WUR was bleeding off zero fuel from the top port of the FD. I think this happened because I used too much copper grease when replacing the little hat on the inside of the WUR which presses against the steel diaphragm. On the second disassembly of the WUR I found the inside reeked of fuel, so I lapped the cell halves on the surface plate until they were as shiny as the FD and made sure the bolts which hold the two halves of the cell together were Very Tight. The instructions I used for the WUR came from k-jet.biz where I had bought the seal kit. Those instructions mention only a single steel diaphragm in the WUR, but my car had two: one with an eccentric hole near the middle, and one plain. The one with the hole was originally placed "above" the plain one in the sandwich, touching the inlet and outlet ports on the cell, so I put it back together that way. I have no idea what it's for, has anyone run into this? This time, the WUR seemed to at least establish a lower control pressure of around 1.2 bar, and not leak any fuel.

Trembling with excitement, I quickly replaced the old fuel injectors and seals with my new ones, mounted FD and WUR back in their places in the engine bay, and attached the injector lines. I replaced some of the rubber intake pipes between the AFM, auxiliary air valve, and idle speed adjusting screw, and began trying to start the car. After much trial and error (fuel spraying from fittings I forgot to tighten in my haste directly into my friend's face for the second time this weekend, realizing after several attempts to start the car that I had long ago pulled the ignition trigger wire off the EZL, oil pouring out of the rocker covers because half the acorn nuts were missing when I got the car and the other half I forgot to tighten, etc etc etc) the car did start and run for about three seconds. YAY! I am elated!!! I have some photos and a recording of the three happiest seconds of my life on my cellphone, I will try to upload these tomorrow. I tried to start the car again, but no joy. I suspect the no-name battery I bought at O'Reilly's two months ago has gone flat with all the cranking from this and the earlier compression/oil system testing I did, but by then it was late on a Sunday night and I decided to leave it for another day. The next thing to do, of course, is worry about the corner-cutting I just did.... I suppose I will find out whether I am in for another disassembly/reassembly cycle this weekend when I try to dial in the WUR and get the car idling continuously. I seriously messed up the screws on the FD and will replace them with Torx heads instantly if I need to touch it again. Sorry for slinging this long rambling post with no pictures your way, I'll try to contain my excitement before I post again. It may have been only three seconds, but it sounds like a beefy machine  ;D

Nuggies
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 26 October 2020, 09:34 PM
I'm glad to see I'm not the only impatient one on the forum haha...
Take heed from fellow member Dave's ("raueda1")  shenanigans with hydro locking a cylinder, it can easily happen if your FD is dumping a lot if fuel into the chamber.  Hilarity will not ensue :o
Title: Re: Restoration of 6.9 #496
Post by: BCK1963 on 27 October 2020, 02:05 AM
The strap behind the front seat is indeed to adjust a lumbar support. Changing the tension of the strap modifies the bulge of the support behind the seat back. In modern cars that would be achieved by an air pump.

I have come across a sheme recently but currently am unable to find it. I will  post it if I can.

     Bernd
Title: Re: Restoration of 6.9 #496
Post by: floyd111 on 27 October 2020, 07:40 AM
Have you found all the parts (numbers) you needed till now?
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 27 October 2020, 06:39 PM
Quote from: daantjie on 26 October 2020, 09:34 PM
I'm glad to see I'm not the only impatient one on the forum haha...
Take heed from fellow member Dave's ("raueda1")  shenanigans with hydro locking a cylinder, it can easily happen if your FD is dumping a lot if fuel into the chamber.  Hilarity will not ensue :o
^^^This!!  Sounds like major progress, but Daniel's right.  Don't fall into the trap of rushing.  I didn't fully appreciate how tiny mistake that just less than 2 seconds ended up ruining my engine.  Be the tortoise, not the hare.
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 18 February 2021, 01:56 AM
Any update on this caper?
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 27 March 2021, 07:42 PM
Hello again, time sure does fly! Progress has been slow and unsteady owing to work, anxiety about the cost of buying parts, and lockdown depression. So, what has happened is:

Last November I had gotten the car to turn over and start, running for fully 3-4 seconds before stalling and becoming unable to restart. This turned out to be the ignition amplifier/EZL thing on the left fender, and may have been damaged because I cranked the engine over without spark plugs during the compression test. I forgot to unplug the green trigger lead from the amplifier, and probably blew out the transistor, oopsies. My multimeter is not great but the coil and ballast resistors were close to nominal. The voltage at numerous points in the resistor network was floating at battery voltage so I felt confident the problem was related to the amplifier not closing the circuit to ground so that the ballast resistors could establish their intended voltages for the coil. I bought a used one from a running car on Ebay for ~$75 and was back in business.

The next few runs, on the order of 15-20 minutes, allowed me to start warming the engine up a little, feel hot water flowing through the upper radiator hose, and burn off the oil that leaked onto the exhaust manifolds. I am sure my neighbors were thrilled to see a big cloud of smoke wafting out of the building: https://drive.google.com/file/d/1BqwdFfhPX3ukgAUhkemxMHIYLDUQcQPB/view?usp=sharing (https://drive.google.com/file/d/1BqwdFfhPX3ukgAUhkemxMHIYLDUQcQPB/view?usp=sharing) It sounded GOOD! I don't remember the suspension coming up, but I will need to fix one thing at a time if I ever want to get there. I wasn't able to dial in the WUR as thoroughly as I wanted and didn't write down what the control pressures were, so I'll have to put that off until such time as I can run it again.

Speaking of, the next item to give up the ghost was the starter motor. It would spin, but not engage the flywheel. I got discouraged, and let it sit for a while... Eventually, I gave up on hammering it in hopes it would stop binding and decided on removing and opening it. This was tricky, but with a set of cheap harbor freight offset wrenches and valuable advice gathered from posts on here, I got it out without removing the steering linkage. The bendix drive was stuck on the armature shaft to begin with, and I certainly sealed its fate with the hammer while trying to remove it, so I've bought a new one. I also bought a set of bushings and brushes. I have pictures of this process and couldn't find a post about it on here, maybe I will make one.

My attention then turned to the ring gear, which I had seen a couple of you replace due to excessive wear. Mine is pretty much hosed in my opinion, and I am worried that there is little sense in putting my rejuvenated starter motor (indeed, any starter motor) into mesh with this grisly piece of work (attached, can't figure out how to post pics in the text...)

I suspect this wear has to do with the extremely loose ignition lock, which makes it hard to engage/disengage the starter because there's no feeling left in it. What do you think? Right now, the available space I have ends right at the garage door so if this needs to be replaced I think I would like to move house so I can get more space. That would also allow me to buy John's engine before someone on CL snaps it up  ;)

I have since been to the DMV and confirmed the car will need to pass smog here in California, both at idle and on a treadmill. My cats are welded in, so if they are bad probably I will need a new exhaust system. I have seen Timevalve recommended by forum members, does anyone know if they make 6.9 exhausts with cats? What does a new exhaust cost?

I am sure I'm forgetting a few details, it has been much too long. With summer coming I would like to get on the road!!!!

Florian
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 27 March 2021, 08:57 PM
Ugh ja that ring gear is toasty :o  big job to replace.  On the 6.9 you have to pull the engine and trans which in itself is no walk in the park.  Best to bang out other jobbies while it's out.  Bon chance ;)
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 28 March 2021, 11:18 AM
Quote from: daantjie on 27 March 2021, 08:57 PM
Ugh ja that ring gear is toasty :o  big job to replace.  On the 6.9 you have to pull the engine and trans which in itself is no walk in the park.  Best to bang out other jobbies while it's out.  Bon chance ;)
Yes, spot on.  Prepare yourself for some soul searching on how much work you want to do when engine is out.  It's such a great opportunity to do jobs you'd probably never consider otherwise! 

Anyway, if you do pull the engine make sure that your engine hoist is HUGE.  It's not just a question of weight.  The boom needs to surprisingly long or you'll eventually get stuck.  Also get a good, heavy duty leveling arm.  The cheap ones with small threads (such as Harbor Freight) will wear out surprisingly fast.  With the right equipment pulling the engine really isn't as bad as you'd expect, though it is laborious.  With undersized or cheap-o equipment there's a very high risk of something very bad happening.  Don't ask me how it know this.   ::)
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 12 September 2021, 01:25 AM
Some updates since last time: I moved across town to a house with 2 driveways, into one of which I had my car towed. I didn't touch it for a few months, but recently have started working toward engine removal. I took off a lot of the easy stuff plus the ac compressor, which was tricky. I got it out without removing the RH engine mount like they do in the book, but their way is probably easiest with how little room you get otherwise. I bought some flare nut wrenches because I was worried about rounding AC and oil/hydraulic line connections with the adjustables, but can tell I will soon also be buying extensions, swivel joints, impact sockets, crows foot wrenches, etc as I suspect they would really ease working on this engine.

I haven't decided what I will do while the engine is out besides the ring gear but there's no shortage of good candidates ;D There is a long list of work that I would be silly not to do with this opportunity. Looking at the age and condition of the parts on this car is making me anxious, and the closer I look the more I want to replace. I am realizing the best would be to just set about replacing all the usual suspects in the suspension, driveline, and brakes before trying to drive it despite how slowly I am moving. I think I am in for a long and expensive period of working on smaller assemblies before I can really see the big picture but I am ok with that because it should make for a great feeling car, albeit not a looker.

To this end I am considering buying an air compressor for blasting, sanding, painting, pressure testing, tools, etc. Does anyone have a setup like this?

Nuggies
Title: Re: Restoration of 6.9 #496
Post by: Flogrates on 12 September 2021, 04:39 AM
Air compressors are so handy, just make sure you get a big enough one
Title: Re: Restoration of 6.9 #496
Post by: rumb on 12 September 2021, 04:19 PM
For sandblasting and painting you would really want @17 cfm compressor.  Yes thats big but you need that much air flow to do the job.
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 19 September 2021, 10:09 PM
I got the engine out today! I had forgotten the three sump oil hoses and the engine dampers. Lifting it out was not difficult, just go slow and try not to damage anything. I had the crane off to the passenger side slightly, which meant the exhaust manifold rubbed against the strut tower on that side, but it's not like I damaged a concours paintjob... Based on Dave's prior work in these threads: https://forum.w116.org/mechanicals/oil-sump-hose-specs/ https://forum.w116.org/mechanicals/6-9-oil-tank-hoses-and-related-issues/ I decided to cut through my hoses with a hacksaw rather than try to disconnect them with no blowtorch and the engine still in the car. I also cut the oil line from the engine to the oil pressure gauge in the instrument cluster (the fitting would not unscrew without also twisting the hardline to which it is affixed at the rear of the engine, no room for counterhold), and the diagnostic sensor on the crankshaft, which I thought was a vacuum line but does enclose two (severed) wires. Next time I do this I will remove the crank pulley beforehand. I didn't this time, and my AC condenser has flattened fins from the pulley and various hoses I did not tie out of the way.

The only real hiccup was the load-leveler I used to pitch the engine up/down. This is the ubiquitous harbor freight 2 ton model. Even with liberal and repeated application of graphite lube, the screw stripped while I was trying to pitch the engine down so that the transmission would clear the radiator support. I am lucky it only froze in place instead of letting the engine slide down the rest of the screw. They used a regular machine screw thread instead of an acme thread, which sprinkled its shavings onto my air metering plate, eek! I have got the engine+trans on a wooden crib for now, while I plan my next move.

FP
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 20 September 2021, 12:08 AM
Nice delivery, doctor  ;)
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 22 September 2021, 12:03 PM
Quote from: McNuggets on 19 September 2021, 10:09 PM
I got the engine out today! I had forgotten the three sump oil hoses and the engine dampers. Lifting it out was not difficult, just go slow and try not to damage anything. I had the crane off to the passenger side slightly, which meant the exhaust manifold rubbed against the strut tower on that side, but it's not like I damaged a concours paintjob... Based on Dave's prior work in these threads: https://forum.w116.org/mechanicals/oil-sump-hose-specs/ https://forum.w116.org/mechanicals/6-9-oil-tank-hoses-and-related-issues/ I decided to cut through my hoses with a hacksaw rather than try to disconnect them with no blowtorch and the engine still in the car. I also cut the oil line from the engine to the oil pressure gauge in the instrument cluster (the fitting would not unscrew without also twisting the hardline to which it is affixed at the rear of the engine, no room for counterhold), and the diagnostic sensor on the crankshaft, which I thought was a vacuum line but does enclose two (severed) wires. Next time I do this I will remove the crank pulley beforehand. I didn't this time, and my AC condenser has flattened fins from the pulley and various hoses I did not tie out of the way.

The only real hiccup was the load-leveler I used to pitch the engine up/down. This is the ubiquitous harbor freight 2 ton model. Even with liberal and repeated application of graphite lube, the screw stripped while I was trying to pitch the engine down so that the transmission would clear the radiator support. I am lucky it only froze in place instead of letting the engine slide down the rest of the screw. They used a regular machine screw thread instead of an acme thread, which sprinkled its shavings onto my air metering plate, eek! I have got the engine+trans on a wooden crib for now, while I plan my next move.

FP
Nice work!  Good move cutting the oil pressure tube instead of trying to remove the fitting, inevitably breaking it and finding a replacement (don't ask how I know this).  Anyway, I used that same damn load leveler.  Anticipation of stripping the threads made me a nervous wreck.  Happily mine survived long enough for me to complete the job, then I threw it away.   My conclusion:  avoid Harbor Freight for mission-critical equipment. Keep us informed on progress!  It's more fun reading about somebody else doing it than doing it yourself!  Cheers,
Title: Re: Restoration of 6.9 #496
Post by: rumb on 22 September 2021, 04:21 PM
Yes, those engines are big and heavy! It's quite satisfying to see the engine out of the car.
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 22 September 2021, 04:33 PM
Quote from: rumb on 22 September 2021, 04:21 PM
Yes, those engines are big and heavy!

I recall a number of 750 lbs for the motor alone, indeed "lightweight baby!" as Ronny Coleman would say:

https://www.youtube.com/watch?v=aRz0QZc8TDE

Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 16 May 2022, 10:27 PM
Oh look at that, it's been another six months! I have at most three months left on my current premises for doing serious work on my car and will try to rush to have it driveable by the end of the summer. I am not sure yet where I will live next, and cannot seem get out of the habit of moving every year or so. In the meantime, I have been buying tools like it's going out of style. I have fixed up an air compressor (new belt, head gaskets, cleaned valve plate, new start+run caps, cleaned motor internals, adjusted centrifugal switch, pressure tested tank) which should be capable of about 12scfm. Its bores are pretty smooth and it looks like it had been run in a very dusty environment, but a cylinder hone costs as much as I paid for the thing... I will leave it alone for now. I've also now got a sandblasting cabinet, a filter/regulator, some hoses, and some air tools courtesy of craigslist, friends, harbor freight, and mcmaster-carr. I scored an unused parts washer from a guy who was restoring an MG but have not bought solvent for it yet.

I have also bought an old BMW motorcycle, which needed some attention too. This is my first bike and so far I absolutely love it. It looks a bit ratty because the last guy started chopping it to make a cafe racer but mechanically it is sound. I relined the gas tank, rebuilt the carburetors, fixed some electrical mistakes, changed all fluids, and registered it. Compared to the car, it is a primitive machine.

The current thing with the car: while trying to degrease the engine+trans I decided to just start taking parts off and labelling them. I think the way forward is to clean/blast/replace everything I can in the engine and suspension, then worry about the cosmetic stuff later. I need to get in the habit of spending time and money _regularly_ on this project soon, or the dream may die!

While trying to undo the inbus screws on the intake manifold, I broke the two foremost bolts as many of you warned me I would. If memory serves, this happens because they are close to the coolant passage and corrode in place. After rounding out the hex recess, I neatly drilled the bolt and tried an extractor. This sheared the head clean off on the passenger side. On the driver's side, I broke the tap socket I was using. I ordered a solid single-piece tap socket, which rounded out as it wasn't hardened. What the hell do I do now? My roommate suggested tapping the hole and using a left-hand threaded screw to try backing the bolts out. My propane torch can't be tipped over far enough to heat the head of the bolt without flaming out, as the liquid sloshes into the burner, so heating it is not an option for now.

I don't post often, but I do enjoy reading nearly everything that gets discussed on this website, how fun it is. Looking forward to a hopefully busy summer!
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 16 May 2022, 11:44 PM
https://m.youtube.com/watch?v=YqFLoq567zk

I quite like this guy  mostly he is into US muscle cars but he has tons of good info gleaned from many years of experience.
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 27 December 2022, 07:07 PM
My bi-annual post is late! The car and engine sat more or less untouched all year from September '21 until September '22. I have tried waiting but the parts remain just as disassembled until I actually do something. Maybe I should try calling the car Christine for better results. I don't have a place to host images and for whatever reason the forum will let me upload images but still not attach them inline. I want them to last as long as the posts, so to the bottom they go. I have more photos and may post them in a trickle over the next few weeks.

In May, my friend and I removed the suspension leaving only the steering gear, torsion bars, and leveling valves in place. We started at the front of the car, separating the upper control arm from the body by removing the 19mm hex bolt and nut from inside the engine bay.

The brake hoses were simply cut since they will be replaced with new ones. The pad wear sensor cable passes through a protective metal tube. I couldn't figure out how to pull the cable back through the tube since the connector is too large, so instead I disconnected the tube from the brake dust shield and left it hanging there. Was this cable terminated after being passed through the tube or am I missing something?

Disconnecting the UCA from the sway bar is done by removing the 24mm bolt that threads into the end of the sway bar, and can only be done once the clamping screws on the sway bar have been backed off. We also separated the tie rod from the knuckle. At this point you can swing the knuckle out (pic 1) and get the ball joint press on the lower ball joint ("supporting joint" in the manual). I used a two-arm one since this joint is tough to remove from the LCA. Tighten the screw until you find yourself squinting, and then tap the screw with a hammer to pop the tapered stud of the ball joint out of the bore in the LCA (pic 2). I didn't catch what size the nut is for the ball joint and don't know if I saved it since the new ball joints from Lemförder come with a nut. I removed the upper ball joint ("guide joint") from the knuckle with the knuckle on the bench since I found that easier.

Removing the front strut was next, two 13mm hex bolts that secure the ball joint to the LCA and three sets of 10mm screws and nuts which hold the strut's top mount into its perch on the body. My top mounts are totally dried out. These are NLA everywhere I checked but I was able to find a supplier in Germany offering a rebuild service, provided your core is rebuildable: https://roland-merz-katalog.de/ersatzteile-mercedes-32-federn-und-aufhaengung Has anyone bought from Roland Merz before? They also offer the bumpstop for the front struts, which I need too. Definitely buy a selection of flare nut wrenches for working on this car, since you will very likely round the fittings on the hydraulic hoses if you do not.

Removing the lower control arms from the car was a bit trickier as the bolts had begun rusting together with the inner sleeves of the bushings. I bought an air hammer, which was a great help in pushing the long 24mm eccentric bolts out. Unscrew the 24mm nut first, and the nut only! I bent one of my eccentric bolts by trying to unscrew it with a pneumatic impact wrench which made it a bear to get out. I don't know how I would have done this with the engine in place. The front subframe tube is very easy to remove, two more 24mm bolts and nuts and it falls right out.

We then moved to the rear of the car. Lots to undo here: cut the service brake hoses, disconnect the parking brake cables, undo the flex disc at the differential input and push the prop shaft forward, separate the sway bar from the rest of the suspension linkage, and release the rear struts from the trailing arms. Now you can start on removal of the rear end. The manual dictates to remove the complete rear axle assembly with diff, trailing arms, etc all still together using a special jack attachment. I found that most of the weight of this assembly is about inline with the rear axle. If the limit stops on the subframe and trailing arms are still intact, you can support the diff with a jack and lower everything to the ground without it falling off, using your hand (or a friend's) to keep the forward  "tips" of the subframe level. This takes only light pressure and prevents the cv axles from excessive misalignment, very convenient. Careful not to damage the brake dust shields like I did... We first loosened the two 17mm screws which hold the small metal brackets between the subframe bushings and body to the body, then the large 24mm screw which passes through the center of the bushing into the body. On one side this was easy. On the other, the bolt had seized to the bushing so tightly that the rubber had to be sheared away by applying LOTS of torque. The bolt came out with the bushing sleeve and metal bracket permanently attached. Get the jack in position, undo the four 13mm screws which hold the rubberized diff mount to the frame floor, and lower away (pics 3, 4, 5)

With the jackstands where we placed them, we were now stuck. It was decided to remove the diff first since it is quite heavy and the cv axles were preventing removal of the complete assembly from beneath the car. Undo the axle bolt at each wheel (I have the later style 13mm head bolt with washer and spacer, yours might be different) and push the axle out of the hub. To get some more room, slide the diff off the jack onto a pile of cardboard. Next, do the four 19mm nuts and washers atop the subframe. Lift the subframe off of the four studs on the diff and pull the cardboard with the diff on it out from under car. Gawk at filthy diff (pic 6). There was now plenty of room to remove the trailing arms from the subframe (two pairs 24mm hex bolts and nuts) and drag all out laterally from beneath the car (pic 7, 8). Remove the rear HPF struts by undoing the hydraulic lines, and at the top by undoing the nuts from inside the trunk (if your fuel tank is already out, like mine) or from inside the car by removing the rear seat backrest. A period of 6 months' hibernation followed....
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 27 December 2022, 07:08 PM
Planning a move to house #3 in November provided some motivation: I thought if I hurry I may be able to at least reassemble the suspension so the car can be towed to its third and final resting place. Wishful thinking but at least I've now got the ball rolling if not the car itself.

Anyway, I started stripping the control arms intent on replacing every moving part in the suspension. The front upper ball joint came out using the smaller lever-style ball joint press easily. Remember to put something between the press and the stud of the ball joint if you need to reuse the joint. My new upper control arms came with ball joints so this was not important.

On to the lower control arms: the three-piece bearing assembly cannot be pushed through from one side. The manual (33-530) states ominously "The remover and installer required for repairing the lower control arm consists of 12 parts." I took a tip from another forum member and sawed off the forward thrust bearing, which allows you to beat the rest of the parts out with a hammer (pics 9, 10). These are bonafide plain bearings and would allow the arm to rotate without any spring force returning them to ride height. The rear bushings consist of a central steel tube, a layer of rubber, and 2-piece outer steel sleeve. The rubber was perished and the outer sleeve corroded in place. Trying to push the bushing out by the tube sheared the rubber, leaving it and the outer sleeve stuck in the control arm. I used a punch against the flange of the sleeve and separated it from the control arm. The two clamshell halves of the sleeve came out easily this way (pics 11, 12). I pressed the bushings out of the front subframe too, this was pretty easy.

Next were the front spindles. First I removed the brake calipers and steering knuckles. Early cars have wheel bearings pressed on to the spindles, luckily not mine. Pop off the grease cap, undo the locking screw, and back off the spindle nut (pic 13). Slide the hub and bearings off the spindle, leaving it bare. You can then easily remove the brake dust shield with three 5mm allen screws leaving the bare spindle (pic 14). The inner roller bearing cage and grease seal come out easily by hand.

With the hub off, it is very easy to remove the brake rotor, five 10mm allen screws with loctite. The hub should now only contain both outer bearing races, which are difficult to remove even with a suitable mandrel. I bought a large brass rod to use as a punch (McMaster 89225K52) which worked nicely. Large diameter (minimum 1"/25mm) is critical here, as the bearing race only protrudes a tiny bit from the inside of the hub. Use a soft metal to avoid marring the bearing seats. I also bought a 3/4" punch (3483A22) for other jobs, but couldn't get the bearing races out with it. I don't have any photos of the front, but the rear is similar and I did take pictures of that for illustration (pic 15). The first few taps are the hardest part, once the race begins to move out better purchase becomes available. It helps to pull the punch toward you as you strike it, to prevent it jumping off the race.

The last thing I did on the front was to pound out the lower ball joints. Googling around for advice, I saw a redneck method of burying the spindle upside down in the dirt to stabilize it and hopefully prevent it from bending. I was able to get both lower ball joints out without heat in a few minutes (pic 16). If I am lucky, I will be able to harvest two new growth spindles next spring!
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 27 December 2022, 07:09 PM
The rear was more challenging. I took apart the parking brake cable and mechanism but there are no pictures and it's all an angry foul-mouthed blur in my memory. I have since bought the two special tools needed for attaching and removing the springs inside, namely, Hazet 4964-1 for the return spring and Hazet 2730 for the hold-down springs. Starting with the trailing arm (pic 17), I removed the brake caliper,  popped off the grease cap for the wheel carrier spindle off (there is a special tool but it is not necessary, use a large open end wrench and work your way around) and loosened the 24mm nut which holds the carrier spindle into the bearings in the trailing arm (pic 18). I also removed the two 13mm screws which hold the bearing cap for the starting torque compensation shackle to the caliper carrier. After that, just slide the trailing arm off.

With the wheel carrier assembly on the bench, I removed the inner snap ring and dust shield for the caliper carrier bearing (pic 19), then used a puller to remove the caliper carrier from the wheel carrier (pic 20). The 50mm socket you need for the crank pulley nut on the 6.9 works nicely for this purpose and it helps to use the brake disc as a stand of sorts. Note that the bearing is destroyed in doing this! You are pulling the inner race off the wheel carrier via the outer race of the bearing, bad news for the bearing. Once the caliper carrier is off, remove the outer snap ring (pic 21) and tap the bearing out with a punch (pic 22). The only marking on the bearing I could find is 361952 A, it is Mercedes part number 001 981 82 25. This part was like $400 at the time so I ordered a generic part number that I found on another forum, 3816-B-2RS-TVH. Now it is available through Mercedes for about $45. it's a sealed double-row ball bearing, just so that the caliper carrier can rotate a few degrees. I've never driven a car with this sort of anti-squat starting torque compensation, hopefully it works well for all the trouble the designers went to!

Next was removing the rear wheel bearing nut. This requires a special axle bearing groove nut socket, which has aftermarket options available. Part numbers I found during my search:

Mercedes 115 589 02 07 00
Mercedes 915 589 02 07 00
KLANN KL-0301
Baum Tools 915-0207
Sir Tools M0027
MMMM 4M-007

I Paid about $120 for mine (Baum), afterwards found them as cheap as $70. Good luck without one. The nut is deformed into two slots on the hub, and must be punched back out before loosening. Ensure the socket is fully inserted and flush with the nut. It takes a lot of torque to remove the nut and there are only four little tabs to apply it. That said, I used the impact wrench for this and the tool held up just fine (pic 23). I am not looking forward to re-torquing this joint. This will allow you to remove the hub from the wheel carrier (pic 24) and remove the bearing outer races with the trusty brass rod as shown earlier.
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 27 December 2022, 07:10 PM
The wheel carrier can now be stripped of the parking brake anvil-thingy, dust shields, and grease seal (pic 25, 26). The grease seal in particular needed a bit of persuasion. I found that using a punch from outside, at an angle toward the axis, helps to lift the sheetmetal seal housing from the wheel carrier (pic 27).

Both wheel carrier and hub will each have one inner bearing race still pressed onto them, against an abutment on the shaft. This made it impossible to get my puller in behind them. Placing the puller jaws on the bearing rollers chipped bits off of the race and then destroyed the cage. Taking a tip from a forum member, I bought a chisel and used it to drive the bearing race away from the abutment until enough room was made for the puller to do its job (pics 28, 29, 30). This was all installed so tightly the lettering on the bearing race was transferred in mirror image onto the spindle. Repeat for a total of four times.

Stripping the rear trailing arms was next. The outer bearing races for the wheel carrier spindle were removed with the divining rod, pretty easy. The trailing arm to subframe bushings came out without much trouble thanks to the puller (pic 31). The shackle which connects the trailing arm to the caliper carrier was much more troublesome. First I tried using the puller to press the shaft out of the shackle (pic 32), which is NOT THE RIGHT WAY to go about it! The shackle, as I later discovered, is S shaped and the shafts are bonded to it with rubber. The right thing is to press the shafts out of the mating component.
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 27 December 2022, 07:10 PM
Next, I reversed the puller and tried to press the shaft out of the trailing arm. I succeeded only in chipping the trailing arm (pic 33). I got fed up and sawed the shackle off so I could fit the trailing arm into my small benchtop press (pic 34). This worked for one side. On the other, no amount of pressing or heating seemed to do anything. I tried dissolving the steel shaft in alum for a few days but gave up after nothing much happened. Finally I cut eight slits into the shaft, leaving only a paper thin sliver of steel. This weakened the press fit enough for me to get the shaft out (pic 35). That's more or less the whole suspension stripped (pic 36), whew!

I had my heart set on re-plating all fasteners and wanted to get as many parts into this "single" batch as I could, including from the engine. I also needed to start preparing to box everything up and it seemed like a good idea at the time to just plow through and take it all to pieces. A few months earlier I had finished removing the intake manifold, despite the two broken bolts still stuck in the heads. I now separated the plenum and runners from each other, and found to my delight that the rubber collars which connect the eight ports were still supple (pic 37). They are about $70 each last I checked since the diameter is different from the M116/7. I also disassembled the throttle linkage, here is a rough layout for reassembly showing the one set of left-hand threads (pic 38). I think I will reuse the plastic bearings, they seemed fine with no noticeable play.

I have a good deal more photos of removing the differential, transmission, harmonic balancer, brake calipers. etc etc etc but no real structure to post them in so I think I will leave it here for now and post those as I complete their respective refurbishment. I was able to get the car onto a wooden frame and towed to the new place, which I have begun preparing for work. I'll make another post about that and some of the refinihsed parts and hardware soon! Thank you all as always for being the friendly and helpful fountain of w116 knowledge that you are.

Nuggies
Title: Re: Restoration of 6.9 #496
Post by: rumb on 28 December 2022, 11:04 AM
Indeed rebuilding the rear axle assemblies is probably the most difficult job I have ever done on my 6.9. It likewise required a whole lot of new tools.  I made the tool for removing and also pressing in the large bearing.

The front brake wear sensor cable is bonded to the tube. I managed to repair the wires and sheath but it was still difficult to get the cable back thru the tube. Still beats what $ ppl want for these if you can find them.

I am supporting the back of the car and stands with a length of 2x4's that goes across the rear of the floor pan.  Seems to hold well, and this way I removed the entire rear subframe complete with everything, and will be able to put back the same.
Title: Re: Restoration of 6.9 #496
Post by: raueda1 on 29 December 2022, 11:28 AM
I truly stand in awe of you guys doing this rear end work. :o  All hail the axle men!!

Quote from: rumb on 28 December 2022, 11:04 AMThe front brake wear sensor cable is bonded to the tube. I managed to repair the wires and sheath but it was still difficult to get the cable back thru the tube. Still beats what $ ppl want for these if you can find them.

I did the same.  It was amazingly difficult because of heat and all the road crap that finds it's way into the tube. Silly design. But it sure looks better after replating.  And it even works! :D
Title: Re: Restoration of 6.9 #496
Post by: rumb on 29 December 2022, 06:12 PM
Check out my car's posts about the large caliper bracket. Hope you didnt bung yours up, they are almost $300 each new.

https://forum.w116.org/test-drive/my-6-9-s/191/

 posts 196-198.  You will see the crude but effective alignment tools I made so you can press them back in at the same angle. they came out.  One tool for each side.

If you want to borrow them, let me know. Also in post 191 you can see the 2 large round tools I made that remove and install the large bearing.
Title: Re: Restoration of 6.9 #496
Post by: daantjie on 18 November 2023, 01:48 AM
Any update on this caper?
Title: Re: Restoration of 6.9 #496
Post by: McNuggets on 24 November 2023, 01:44 PM
Haven't touched it all year. I aim to resume work in January.
Title: Re: Restoration of 6.9 #496
Post by: andrewk on 25 November 2023, 08:56 AM
Quote from: McNuggets on 24 November 2023, 01:44 PMHaven't touched it all year. I aim to resume work in January.

Keen to see how you go with everything, especially the front subframe if you get into the bushings and bearings there.

NB: I replaced the ring "connector" seals (100-140-04-65) and they were 46.50 USD each from Classic Center Mine were definitely too stiff to reuse without headaches.

Good luck