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6.9 #521 Restoration

Started by wbrian63, 28 August 2013, 06:40 AM

wbrian63

The proper classification for any "for sale" W116 car, no matter how visually perfect should be, in my opinion "no visible rust"

We know the rest of the story.
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V

wbrian63

Methods employed to pull the subframe box straight (or should I say un-dented?) involved using a large welding clamp to pull most of the dent out. To coax some of the other smaller dents, I thought I could use a standard mechanics pry bar, but the angles weren't right.

The size and width of the foot of the pry bar are good


But there's not enough bend behind the foot where it meets the shaft to prevent the shaft interfering with the edge of the subframe


So I made one.

This is fashioned from a piece of 1/2" round bar. I heated the end of the rod to a reddish-orange tone, then beat the snot out of it on the anvil of my bench vice. Heat - beat - repeat.


In the previous image, I've already formed the "spoon" on the end, I've already put one bend in it, and and I'm preparing to create yet another elbow to provide better access.

The advantage of doing it this way is that I can adjust the angle of the foot and ankle of the tool to suit where I need to apply force.

In all cases, I made sure the pry against some part of the subframe assembly - wouldn't do to use the floor pan as a pry point...

I'm not certain if I'm "done" with this section, but it looks a far sight better than it did when I started:


Since I have a NOS transverse subframe for the left-hand side, thanks to Mirafioriman, I didn't have to be so careful in my removal efforts. I just used my small right-angle pneumatic grinder fitted with a thin cutoff wheel, and sliced the part off the car:




Somewhat serendipitous that I'm fixing the subframe, as my floorpan repairs above this section left some really nasty-looking welds.


The challenge with pulling the dents out of the main subframe channel is that there's a shallow dent that stretches for a good distance too far away from the opening, so I'm having to use the threaded rod as a pulling tool.


It's coming along nicely, and I've developed some technique to the process, but it is slow.

First thing I did was to get one of my support stands for my dry-cut saw and use that as a place to set the torch while I'm not using it. Before, I had to extinguish and relight the torch for each pull.

Second was to learn how to heat and pull the dents. My first attempt was to heat around the attachment point for the rod. Pulling from there just left an outward dimple in the middle of an inward dent.

Subsequent efforts involved heating around the pull point, but avoiding the pull point entirely. Since the dent is fairly shallow and mostly flat, that allowed me to pull the section closer to flat without pulling the middle up too far.

The threaded rod works good, but it is slow. I have to cut it free, move the pulling bar, then weld the rod back in place for the next pull. Periodically, I have to stop and grind away all the welding nubs that are left when I cut away the threaded rod. It's hard to see how flat (or not flat, in my case) the substrate metal is when the plane is pockmarked with a bunch of welding stubble.

I have yet to reinstall the passenger transverse subframe for a couple of reasons.
1) I wanted to see if the gap in the floor pan was the same on the left-hand side of the car - answer: it is.
2) I'm not certain if I'm satisfied with the dent-removal process used thus far. As noted previously, it's a lot better than it was when I started, but it could be better still. Some of the techniques required to improve on the work done thus far will require easy access to the inside of the subframe channels, and that won't be possible once the transverse piece is reinstalled. Jury is still out here.

I'm away from the shop for the next couple of weeks. My better half had reconstructive ACL surgery on the right knee this morning. Providing moral/physical support will be my primary focus for a number of days.

Things you never want to hear an orthopedic surgeon say as he's browsing through the MRI images of your knee: "An here - right here, is where your ACL Should Be..."

Modern surgery is a wonderful thing, and a cadaver provided the replacement ligament which will act as a lattice for the body to replace it with native ligament tissue over the next year or so.
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V

Casey

This is perhaps the most amazing thread I've ever seen.  What an impressive load of work!  Good luck with the knee...

wbrian63

Thanks, Casey. I'll try to keep up the good fight - it's been 2+ years already, and I'm not sure if I can see the end yet...
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V

wbrian63

And just like that, another 2 months have gone by since my last substantive post. What has been accomplished? Sadly (or should I say "typically"?) not much. However, I do have some pictures...

As noted previously, the process of pulling the dents from the front sub-frame involved using a torch – here's an example where I'm pulling multiple layers – the all-thread in this case is inserted through a hole drilled through all the layers, and a nut and large washer hold it in place from behind.



Careful application of heat:



And the subframe is flatter than when I started. (The pulling rod has been moved – it was previously in the hole indicated by the red rectangle):



The intent of all this work is to pull the dents out of the subframe to make it more presentable. There was no indication that this work "needed" to be done – I just never liked how badly dented the pieces were. After all of this, it would be a shame if it happened again – so how to prevent it?

I had thoughts of inserting some heavy plate inside the subframe channels while the diagonal braces were out, but vetoed that idea – there are way too many holes in the subframe – water will get in, and having two pieces of metal closely positioned will just give a place for water and grit to form mud, and rust is the result, no matter how good the cavity wax job is. Also – unless I could get the plate nestled tightly against the subframe bottom, the first application of a jack would put a dent in the subframe again.

More analysis of how the dents occur indicates that the issue is that the horizontal sections of the subframe which bear against the jacking pad aren't strong enough to support the full load of the front of the car with the massive iron block V8. Looking at the dents, especially in the likely jacking area where the transverse subframe meets the main subframe channel, the sides of the subframes are largely unaffected – so let's take advantage of that strength.

Enter the "crutch" – fashioned from 3/8" x 2" flat bar (8.5mm x 51mm):


It is to be installed thusly:




It bears across the side of the main subframe, and rests on top of the part of the framework that forms the pocked for the cross member that supports the rear control arms.



Properly installed, there's a gap between the crutch and the subframe.



And here's the passenger side all put back together again – this is the one where I had the NOS transverse piece – looks pretty good once all is said and done:



I was "lucky" enough to run across an auction on eBay for both pieces of the front bumper support. If I recall, the inner piece is still available from MB, but the outer section is NLA. A few (more than a few, but still a "steal") dollars later and the part arrived:



In place beneath the still-installed bumper support – you can see the distortion in the original part just to the left of the rotisserie vertical support.



The part arrived in a box, but it was wrapped in some newspaper dating back to 1977 – I got a real chuckle when I saw this:



Further investigation reveals that originally the part was sent loose in the US Mails – the left hand side of this image is a mail meter label:



Part of the challenge in getting the original part out of the car is that there are a number of places where it was spot welded to the frame where the placement of additional parts (like the radiator/headlight support frame) now block access to the welds. Since the original part is destined for the recycling bin, I can go in from the front:

   

You can see the 3 spot welds at the back of the support cavity:



A lot of work later and the old part was out, revealing many areas where rust was taking hold.



The frame channels, once open to viewing for the first time in 4+ decades, reveal cavity wax and a lot of grime...



Before the new part could be installed, all of the holes drilled in the frame to release the original part needed to be filled:



Where I can, I want to remove as much grime from inside the frame – I've got a consumer-grade steam cleaner that helped some. The best result came from chemistry – good old brake cleaner...



Before:


After:


Oddly, I don't have any full pictures of the bumper support fully installed – just sectional views. All bare metal surfaces were prepped with 2-part epoxy primer prior to welding. This photo is very recent (1st week of January, 2016)– the actual work was done in November 2015. The flash rust will be cleaned before the part is re-primed.



You can see lots of plug welds, plus I stitch welded the primary frame supports where they join to the bumper support, in addition to plug welding. Should be strong enough:

After the bumper was done, I started the long process of checking what else remains before I start prepping for paint. I found (not surprisingly) more things that needed to come off. This is the support for the 5th sphere under the left-hand fender:



Based on how much rust I found in other areas, I decided to remove it. The technician at MB must have been paid by the weld, because they went overboard on this bracket – there are 11 spot welds:



Surprise!!!





Process was the same as elsewhere on the car – media blast to remove rust, weld up holes, coat with epoxy primer and reattach. You can see the alignment hole I drilled near the top left of the bracket. Makes
it possible to put the part back exactly where it was removed:



The big dent in the floor pan I discussed in the previous posting was easily accessible from a hole inside the car and has been "mostly" dealt with using a ½" round bar and a medium size hammer. I'll need the help of an additional person to hold a body dolly to take a few small dents out, but that problem was really a non-issue.
The last step before I start cleaning for underside primer is to make sure that all floor pan work is done. I don't want to discover after the primer is on that I've got to cut something out and weld it back.
The right side rear floor pan still had the sound dampener pad in place – what a complete pain to remove:



The actual process of chipping the material out wasn't a big deal. Getting rid of the contact adhesive was another matter – that took a Long Time...
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V

Wrighttbenz

All I can say is man that is intense. You must love working on that car. I would question weather it will ever be as good as it was from the factory. How will you get all of the under coating and panels back the way they were. To deep into it in my opinion but I will enjoy reading your progress.

ptashek

Quote from: Wrighttbenz on 09 February 2016, 12:51 AMI would question weather it will ever be as good as it was from the factory.

Why wouldn't it be?
I'm pretty sure it'll be much better, given the dedication and attention to detail.
1993 "Pearl Blue" W124 280TE
1988 "Arctic White" W124 200T
1979 "Icon Gold" W116 450SE

wbrian63

Some aspects of the car will be better than before, some not so much. Once it's all primered and covered in schutz (undercoating spray), I doubt any of the "less than perfect" sections will be visible.

Wrighttbenz - I did take notice of your purchase of an euro 6.9. I wish you the best. I you want to come to my thread and read on the progress there, I welcome you. If you have suggestions to offer - feel free. I have a thick skin. If you have criticisms to offer - feel free - I can always learn from someone else's experience. If you have comments that are of no use - feel free to visit another thread.

I've worked Very Hard on bringing this car back from where it was to where it is. Whether I would have done this if I had known how bad the condition truly is is a moot point - I've done it and here I stand. Whether others could have done a better job is also not up for debate, as the answer is "of course" and "of course not", depending the ability of the person. I've done what I could with the skills and tools that I have.

Your journey has just begun. Anyone that has purchased a car that has been sitting for 15 years is in for a real challenge. My 6.9 was running when I purchased it - yours wasn't - and still isn't.

A suggestion - before you pour one ounce of fuel into the tank - pull the tank sender (it's accessible once you remove the tray that houses the first aid kit on the rear package shelf) and have a look see in the tank. Unless the basic laws of metalurgy were somehow abandoned in your situation, unless the tank was completely dry when the car was stored - what you've got now is a big tank full of rust.

Regards
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V

daantjie

Brian I see you had a dent in the floor board. Was this easy to knock back out? Did you notice any effect on the B pillar because of the dent?
My recent accident caused a dent through the rocker panel and into the floor board. Now seems like the door gap is not uniform and the door closing has been compromised  and it looks like the B pillar is the culprit.
Would like to get your take on this.
Cheers.
Daniel
1977 450 SEL 6.9 - Astralsilber

Jed

Brian,
Your progress continues to astound me!! Those pictures are incredible! Keep up the great work and thanks for the regular posts that continue to motivate the rest of us.

Jed (in Detroit)
1979 Mercedes 6.9 #5206 - restored
1979 Mercedes 6.9 #6424 - ongoing restoration
1976 Mercedes 6.9 #484 - restoration?

Wrighttbenz

Quote from: wbrian63 on 09 February 2016, 10:51 AM
Some aspects of the car will be better than before, some not so much. Once it's all primered and covered in schutz (undercoating spray), I doubt any of the "less than perfect" sections will be visible.

Wrighttbenz - I did take notice of your purchase of an euro 6.9. I wish you the best. I you want to come to my thread and read on the progress there, I welcome you. If you have suggestions to offer - feel free. I have a thick skin. If you have criticisms to offer - feel free - I can always learn from someone else's experience. If you have comments that are of no use - feel free to visit another thread.

I've worked Very Hard on bringing this car back from where it was to where it is. Whether I would have done this if I had known how bad the condition truly is is a moot point - I've done it and here I stand. Whether others could have done a better job is also not up for debate, as the answer is "of course" and "of course not", depending the ability of the person. I've done what I could with the skills and tools that I have.

Your journey has just begun. Anyone that has purchased a car that has been sitting for 15 years is in for a real challenge. My 6.9 was running when I purchased it - yours wasn't - and still isn't.

A suggestion - before you pour one ounce of fuel into the tank - pull the tank sender (it's accessible once you remove the tray that houses the first aid kit on the rear package shelf) and have a look see in the tank. Unless the basic laws of metalurgy were somehow abandoned in your situation, unless the tank was completely dry when the car was stored - what you've got now is a big tank full of rust.

Regards

I didn't mean at all to offend anyone. The amount of work you have taken on is amazing and well beyond what I could ever undertake. I have brought cars back that have sat for many years in the past and I appreciate the advice on the fuel tank. I have already drained the tank and ordered new hoses and fuel pump bits. I have had pretty good luck in the past and have only had to remove one tank for cleaning and that actually probably wasn't necessary. It isn't rust that I generally find especially in a high quality car like this. More so it is plugged lines from the varnish that gunk's up.
I will have her started soon. It started when it was parked and I am sure it will run again.

arcijack

this has been my inspiration on my car, I had plans scrap, but after seeing and following this thread I decided to keep her, my skill level is not up to this standard, but I have learned a lot , many bad welds , I plan to take apart and try again, thanks Brian, keep at it. 

wbrian63

Quote from: daantjie on 09 February 2016, 04:18 PM
Brian I see you had a dent in the floor board. Was this easy to knock back out? Did you notice any effect on the B pillar because of the dent?
My recent accident caused a dent through the rocker panel and into the floor board. Now seems like the door gap is not uniform and the door closing has been compromised  and it looks like the B pillar is the culprit.
Would like to get your take on this.
Cheers.
If we're talking about the same dent (sad that there were several), the biggest one was under the rear seat where the rear subframe "Y" shaped frame that provides alignment and torsional structure to the rear subframe mounts. Likely from someone attempting to jack the car up from the wrong spot. It came out very easily with some persuasion from inside the car via some access holes under the rear seat platform. That was the biggest dent in the floor pan. Location for that dent would have had zero effect on the B-pillar.

There were a few other small dents that were easily pounded out with a dolly and a body hammer - all too small to have any structural effect.

If you're now seeing alignment problems where the front door latches to the B pillar, you've either got movement in that pillar, or in the A pillar where the door hinges attach. I would think that any movement in the B pillar sufficient to cause alignment problems would possibly telegraph to the roof - but I could be wrong.

There was someone selling (if I recall correctly) a B pillar on eBay recently. Same fellow I bought my new front bumper support from. The vendor name is rcv225, but I don't see any active auctions. Of course, it may not be the right B pillar, as they are handed parts.

Sorry I'm not more help. Good luck in your quest.

Regards
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V

wbrian63

Quote from: Wrighttbenz on 09 February 2016, 05:16 PM
Quote from: wbrian63 on 09 February 2016, 10:51 AM
Some aspects of the car will be better than before, some not so much. Once it's all primered and covered in schutz (undercoating spray), I doubt any of the "less than perfect" sections will be visible.

Wrighttbenz - I did take notice of your purchase of an euro 6.9. I wish you the best. I you want to come to my thread and read on the progress there, I welcome you. If you have suggestions to offer - feel free. I have a thick skin. If you have criticisms to offer - feel free - I can always learn from someone else's experience. If you have comments that are of no use - feel free to visit another thread.

I've worked Very Hard on bringing this car back from where it was to where it is. Whether I would have done this if I had known how bad the condition truly is is a moot point - I've done it and here I stand. Whether others could have done a better job is also not up for debate, as the answer is "of course" and "of course not", depending the ability of the person. I've done what I could with the skills and tools that I have.

Your journey has just begun. Anyone that has purchased a car that has been sitting for 15 years is in for a real challenge. My 6.9 was running when I purchased it - yours wasn't - and still isn't.

A suggestion - before you pour one ounce of fuel into the tank - pull the tank sender (it's accessible once you remove the tray that houses the first aid kit on the rear package shelf) and have a look see in the tank. Unless the basic laws of metalurgy were somehow abandoned in your situation, unless the tank was completely dry when the car was stored - what you've got now is a big tank full of rust.

Regards

I didn't mean at all to offend anyone. The amount of work you have taken on is amazing and well beyond what I could ever undertake. I have brought cars back that have sat for many years in the past and I appreciate the advice on the fuel tank. I have already drained the tank and ordered new hoses and fuel pump bits. I have had pretty good luck in the past and have only had to remove one tank for cleaning and that actually probably wasn't necessary. It isn't rust that I generally find especially in a high quality car like this. More so it is plugged lines from the varnish that gunk's up.
I will have her started soon. It started when it was parked and I am sure it will run again.

I will admit to being a bit sensitive when someone questions why I would attempt what I have. There are far too many people in this world that think that anything they wouldn't personally attempt is "wrong" and I bristle easily at those type of comments.

I welcome your clarification and wish you the best in your efforts to re-road your recent purchase. Hopefully, your fuel system proves a quick and easy fix.

#521 had a Completely Pristine fuel tank before I let it sit with fuel in it for 3 years and rust set in. Then I had another fuel tank from my first 6.9 (#1164) that I parted out which was equally clean, but had a couple of poorly patched holes in the side that faces the trunk. Likely from someone mounting something to the modesty panel and screwing clean through into the tank. I figured I'd weld the holes up - the patches were nothing more than rubber washers with sheet metal screws. No worries on explosion in a tank that has sat empty for 3 years. However, what I didn't realize is that there's some sort of plastic baffle in the top of the tank that doesn't take kindly to the heat from a mig welder. I set that to smoldering, and it melted and dripped into the tank. Not a total loss, but I've not been able to figure out what to do about it. Since I've got two basically useless tanks, I think I'm going to cut the rusty one apart, remove the intact baffle assembly and try to weld the tank back together. If I'm sucessful, then I'll cut the good tank apart and replace the baffle and hopefully be able to re-weld it...

Best wishes and best of luck to you.
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V

daantjie

Quote from: wbrian63 on 10 February 2016, 08:58 AM
Quote from: daantjie on 09 February 2016, 04:18 PM
Brian I see you had a dent in the floor board. Was this easy to knock back out? Did you notice any effect on the B pillar because of the dent?
My recent accident caused a dent through the rocker panel and into the floor board. Now seems like the door gap is not uniform and the door closing has been compromised  and it looks like the B pillar is the culprit.
Would like to get your take on this.
Cheers.
If we're talking about the same dent (sad that there were several), the biggest one was under the rear seat where the rear subframe "Y" shaped frame that provides alignment and torsional structure to the rear subframe mounts. Likely from someone attempting to jack the car up from the wrong spot. It came out very easily with some persuasion from inside the car via some access holes under the rear seat platform. That was the biggest dent in the floor pan. Location for that dent would have had zero effect on the B-pillar.

There were a few other small dents that were easily pounded out with a dolly and a body hammer - all too small to have any structural effect.

If you're now seeing alignment problems where the front door latches to the B pillar, you've either got movement in that pillar, or in the A pillar where the door hinges attach. I would think that any movement in the B pillar sufficient to cause alignment problems would possibly telegraph to the roof - but I could be wrong.

There was someone selling (if I recall correctly) a B pillar on eBay recently. Same fellow I bought my new front bumper support from. The vendor name is rcv225, but I don't see any active auctions. Of course, it may not be the right B pillar, as they are handed parts.

Sorry I'm not more help. Good luck in your quest.

Regards

Thanks Brian!
Daniel
1977 450 SEL 6.9 - Astralsilber