The Forum

Garage => Mechanicals => Topic started by: jllgd on 03 October 2019, 04:28 PM

Title: Mercedes 6.9: Water Pump Overhaul
Post by: jllgd on 03 October 2019, 04:28 PM
Gents,
I have unfortunately now a leaking water pump.
What parts are needed to overhaul and rebuild the pump?
Is it normally just the mechanical seal that's leaking?
Plus some gaskets?
Are these parts easily available?
Can the repair work be done at any good mechanic repair shop?
Are rebuilt water pumps available?
Thanks
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: UTn_boy on 03 October 2019, 09:10 PM
You ask a very loaded question that requires a lengthy answer.  So I'm going to stick to the "Cliff" notes version.

-Yes, they are re-build-able
-No, most shops will destroy the impeller (a part no longer available) when attempting to rebuild it, so don't do that.
-Special tools are required to disassemble and reassemble the pump.  They have to be made or adapted from similar tools. 
-The rebuild kit, part number 100-586-05-20, is no longer available. 
-The individual parts that makes up the rebuild kit....some are still available (gaskets), but the seals, bearings, main shaft, and impeller are not. 
-Mercedes Classic does offer a rebuilt water pump on a core exchange basis, part number 100-200-32-01-80.  It currently has a list price of $1,485.00.  Classic can likely do better on the price if you talk to Tom Hansen. The pump can be ordered through any dealership, too.  However, some will charge more than list or less than.  You never know. 
-The actual job of removal and re-installation of the water pump is not a job for the back yard.  It's pretty straight forward to someone with experience, but accessibility to the water pump is attained only after removal of several things like the fan, harmonic balancer (another doozy of a job), and distributor housing.  Unless you have a lot of time to learn how to do it and the ability I don't recommend trying it as a first time type of job......only because it's so involved and unlike any other engine I've ever worked on. 
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: TJ 450 on 03 October 2019, 10:45 PM
It certainly is a challenge. Rebuilt pumps were available on eBay a while back, it would be worth checking.

When this job is done, you might want to consider replacing the front crank seal given the whole front of the engine will be pulled apart.

Tim
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: raueda1 on 03 October 2019, 11:13 PM
Quote from: UTn_boy on 03 October 2019, 09:10 PM
You ask a very loaded question that requires a lengthy answer.  So I'm going to stick to the "Cliff" notes version.

-Yes, they are re-build-able
-No, most shops will destroy the impeller (a part no longer available) when attempting to rebuild it, so don't do that.
-Special tools are required to disassemble and reassemble the pump.  They have to be made or adapted from similar tools. 
-The rebuild kit, part number 100-586-05-20, is no longer available. 
-The individual parts that makes up the rebuild kit....some are still available (gaskets), but the seals, bearings, main shaft, and impeller are not. 
-Mercedes Classic does offer a rebuilt water pump on a core exchange basis, part number 100-200-32-01-80.  It currently has a list price of $1,485.00.  Classic can likely do better on the price if you talk to Tom Hansen. The pump can be ordered through any dealership, too.  However, some will charge more than list or less than.  You never know. 
-The actual job of removal and re-installation of the water pump is not a job for the back yard.  It's pretty straight forward to someone with experience, but accessibility to the water pump is attained only after removal of several things like the fan, harmonic balancer (another doozy of a job), and distributor housing.  Unless you have a lot of time to learn how to do it and the ability I don't recommend trying it as a first time type of job......only because it's so involved and unlike any other engine I've ever worked on.
It's a pain, to be sure,  but I'm not so sure about the harmonic balancer part.  I just pulled mine without doing that.  My engine was out of the car, maybe that's why.  And if it's a USA car then there's also some kind of smog valve thing as well.  Certainly easiest with radiator removed and probably the AC radiator too for access to front of engine.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: Randys01 on 04 October 2019, 04:08 AM
I have done this job with the engine in situ and it's tricky.!! but you do not have to remove the  harmonic balancer. With the motor out, a cake walk. !Exchange /change over  pumps can often be found on Ebay . There are 2 types. so called square and round. From memory the pumps are not interchangeable with the water pump housing. That is- square pump to square housing and vice versa.
The original double sealed bearing canniste r is no longer avail. so I assume rebuilds have crafted their own drive spindle and fitted up std bearings. Internal seals are avail aftermarket but he waterproof compression seal would seem to be MB specific.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: PosedgeClk on 04 October 2019, 09:44 AM
This is probably one that I am going to take on soon. The weep hole at the top of my pump is open which worries me a bit. I originally purchased the car to drive it as quickly as possible from coast to coast, but I missed the event, and it is probably a good thing because I did not discover that problem until the last moment. I had a jerry can of deionized water, but that does not go that far when you are a hundred miles from the next small town in the deserts of New Mexico or California.

I have a small machine shop and can make parts and tools. There are several NLA parts which I might try to produce with my capabilities, and the water pump or parts for the water pump are on that list.

I don't think that I would be threadjacking here to ask for what the most difficult/unavailable parts are. If the impeller is made of sheet metal, that is easy enough. If there is some obscure shaft seal that is NLA and not a standard size, it might be a little more difficult.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: daantjie on 04 October 2019, 10:27 AM
Here is a seal on ebay:

https://www.ebay.com/itm/Mercedes-450SEL-6-9-water-pump-sealing/113869133896?hash=item1a83211848:g:EgYAAOSwMG1dZq8i
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: jllgd on 04 October 2019, 07:03 PM
Thanks to all for your thoughts and comments. Much appreciated indeed.
And thanks for the eBay link.
Since the mechanical seal is available, (ref eBay) but not the bearing and shaft, I am unsure what the best option is?
I don't know the condition of these internal parts yet, sine pump is not removed from car.
The refurbished pump from Classic Center is a tad expensive.
Thanks
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: UTn_boy on 04 October 2019, 10:40 PM
Quote from: Randys01 on 04 October 2019, 04:08 AM
I have done this job with the engine in situ and it's tricky.!! but you do not have to remove the  harmonic balancer. With the motor out, a cake walk. !Exchange /change over  pumps can often be found on Ebay . There are 2 types. so called square and round. From memory the pumps are not interchangeable with the water pump housing. That is- square pump to square housing and vice versa.
The original double sealed bearing canniste r is no longer avail. so I assume rebuilds have crafted their own drive spindle and fitted up std bearings. Internal seals are avail aftermarket but he waterproof compression seal would seem to be MB specific.

Are you sure about that?  I've done several water pumps on 6.9 engines, and every one of them I've had to either remove or halfway pull off the balancer so the impeller clears the water pump housing.  I usually just remove the balancer so I can do the front crankshaft seal while I'm down there.  Maybe the early and late water pumps were different enough to allow clearance?  Just guessing.  If I recall all of the ones i've done were late models. 

JLLGD,

the seal alone isn't of much use if you don't have the other parts to do the rebuild with.  You may just have to buy a rebuilt pump.  Alternatively, try to contact Martin Werminghausen at http://www.600airsuspension.com/ (http://www.600airsuspension.com/) and ask him if this is something he'd consider doing for you.  Though, you'll still pay quite a bit.  Without the parts being easily/readily available and the lack of knowledge out there to do the rebuild our hands are somewhat tied. 

PosedgeClk: 

The impeller is made from cast iron.  A sheet metal impeller I wouldn't recommend due to the volume flow requirements and the massive expansion rate of the thin sheet metal.....which could easily free spin on the shaft give how close it is to the water pump housing when installed.  Because it's made of cast iron, one can easily understand why they're so fragile when removing.  The slightest snag on the shaft and "SNAP", the impeller literally breaks in half.  A torch and liquid nitrogen are necessary when removing the impeller.   Makes all the difference in the world.  But the rebuild kit used to come with a new impeller because the chances of it breaking were about 100%. 

So here is what the rebuild kit was comprised of when it was available:

100-201-11-80 Lower water pump housing to block gaskets, two required, still available.
100-201-10-80 Upper water pump housing to block gasket, no longer available.
100-201-13-80 Water pump to water pump housing gasket, still available
100-201-03-07 Impeller, no longer available
000-201-36-19 Shaft seal, no longer available .....sans the ebay link that daantjie posted. 
007603-020404 copper sealing washer for water line connection to top of water pump housing, still available
100-203-00-80 Gasket for thermostat housing to top or water pump housing, still available
015-997-23-48 seal ring for thermostat housing to thermostat, still available
000-980-10-15 main shaft with bearing, no longer available
117-201-01-39 hub for viscous fan clutch, no longer available
007346-004014 Roll pin for connection of main shaft to water pump, no longer available.

The parts in red are what is actually needed to rebuild the water pump.  The rest of the parts are seals and gaskets that can easily be made/procured locally.  Maybe all of this is useful to someone, or maybe not.  At least the part number references are out there now. 

Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: Harv on 04 October 2019, 11:07 PM
Quote from: UTn_boy on 03 October 2019, 09:10 PM
-Mercedes Classic does offer a rebuilt water pump on a core exchange basis, part number 100-200-32-01-80.  It currently has a list price of $1,485.00.  Classic can likely do better on the price if you talk to Tom Hansen. The pump can be ordered through any dealership, too.  However, some will charge more than list or less than.  You never know. 

My go-to dealer shows a price of $1,098.90, a 386.10 discount from list. Core is $111.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: UTn_boy on 05 October 2019, 12:45 PM
Quote from: Harv on 04 October 2019, 11:07 PM
Quote from: UTn_boy on 03 October 2019, 09:10 PM
-Mercedes Classic does offer a rebuilt water pump on a core exchange basis, part number 100-200-32-01-80.  It currently has a list price of $1,485.00.  Classic can likely do better on the price if you talk to Tom Hansen. The pump can be ordered through any dealership, too.  However, some will charge more than list or less than.  You never know. 

My go-to dealer shows a price of $1,098.90, a 386.10 discount from list. Core is $111.

Do you remember that water pump you got for me?  Remember how the impeller wouldn't clear the housing because the harmonic balancer was in the way, and the impeller ended up breaking? 
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: Harv on 05 October 2019, 07:58 PM
Quote from: UTn_boy on 05 October 2019, 12:45 PM
Do you remember that water pump you got for me?  Remember how the impeller wouldn't clear the housing because the harmonic balancer was in the way, and the impeller ended up breaking?

Yepp. I broke two hex bits on it as well. Granted, they were cheapo bits and warrantied out, but I didn't expect that. I had the radiator out and it was still a hell of a job to get off.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: Randys01 on 06 October 2019, 02:53 AM
"Are you sure about that?  I've done several water pumps on 6.9 engines, and every one of them I've had to either remove or halfway pull off the balancer so the impeller clears the water pump housing.  I usually just remove the balancer so I can do the front crankshaft seal while I'm down there.  Maybe the early and late water pumps were different enough to allow clearance?  Just guessing.  If I recall all of the ones i've done were late models. "

.oh yeah.  that's a job you don't forget .. :'(!!   .but I'm inclined to think the round pump variant [mine] could be the key to it. My car is late model Dec 78 and is round pump. It wasn't a  matter so much of late or early...pump style to some degree depended on destination.
I did a whole paper on this topic for the M100 Lodestar mag about 5 years ago............inc how to rebuild your own pump yourself....
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: PosedgeClk on 06 October 2019, 03:16 PM
Quote from: UTn_boy on 04 October 2019, 10:40 PM
The parts in red are what is actually needed to rebuild the water pump.  The rest of the parts are seals and gaskets that can easily be made/procured locally.  Maybe all of this is useful to someone, or maybe not.  At least the part number references are out there now.
Thank you for the great deal of detail.

Cast iron is doable on a small scale as is a stainless billet impeller with a 4 or 5-axis CNC machine. I would err away from cast as it might take me a few attempts before getting it tweaked enough to not grenade. Someone out there with a little experience in the area could probably pull it off on the first try.

The 6.9 is "under construction" in Chattanooga. Maybe I can head up to your area one weekend when it's road-worthy and we can talk W116 over a beer.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: UTn_boy on 06 October 2019, 03:32 PM
Quote from: Randys01 on 06 October 2019, 02:53 AM
"Are you sure about that?  I've done several water pumps on 6.9 engines, and every one of them I've had to either remove or halfway pull off the balancer so the impeller clears the water pump housing.  I usually just remove the balancer so I can do the front crankshaft seal while I'm down there.  Maybe the early and late water pumps were different enough to allow clearance?  Just guessing.  If I recall all of the ones i've done were late models. "

.oh yeah.  that's a job you don't forget .. :'(!!   .but I'm inclined to think the round pump variant [mine] could be the key to it. My car is late model Dec 78 and is round pump. It wasn't a  matter so much of late or early...pump style to some degree depended on destination.
I did a whole paper on this topic for the M100 Lodestar mag about 5 years ago............inc how to rebuild your own pump yourself....

Well, as you said it's a job you don't forget, and I remember very well the pump impeller not clearing the water pump housing without removing or sliding the balancer back a bit.  Note that I'm not the only one that has experienced this.  I'm not making this up!  Speaking of of M-100 and Lode Star, what in the world is going on with that entity?  I can't renew my membership, the website won't let me do what I used to be able to do regarding commenting and viewing, and when I contacted someone regarding the aforementioned I was told to call the web host company.

PosedgeClk   In Chattanooga?  I didn't even know there was anyone competent enough in that area to work on a vintage Mercedes, much less an M-100.  Just..Be careful.  Regardless, you're welcome any time!  I'd love to chat and visit! :) 
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: jllgd on 06 October 2019, 03:50 PM
Thanks to all for replying and commenting on this 6.9 water pump subject.
And a special thank to UTn_boy for summarizing all the pump parts with their part numbers. I think it's the first time I've seen these listed like that.
Appreciate it.

As it looks now I might purchase a refurbished pump from Mercedes Benz.
And as far as I know these are in stock.

I probably want to keep the old core for later use, since the core value is only about $111 as Harv mentioned. I believe I can keep the core if I want to?
Perhaps some clever mechanic can have it refurbished later.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: UTn_boy on 06 October 2019, 04:38 PM
I try to give part numbers out as often as I can.  They're extremely helpful!  Sadly, Mercedes has mandated a new policy to where dealerships can no longer give out part numbers.  Granted, it you have a close relationship with your parts guy that may not apply to you, but for most of us it will apply. 

And yes, you can keep the core.  You just won't get the $111 back they charge you up front.  And don't forget about seeing if Martin Werminhausen can rebuild the pump.  He's really good at what he does!  :)
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: 3l33ter on 06 October 2019, 06:22 PM
Quote from: Randys01 on 06 October 2019, 02:53 AM
I did a whole paper on this topic for the M100 Lodestar mag about 5 years ago............inc how to rebuild your own pump yourself....

I haven't had my 6.9 (nor known about the 6.9 specific communities) long enough to have that magazine. Any chance this paper / tutorial is somewhere online?



Timely topic for me - I am in the midst of reassembling my 6.9 engine after some major work. I was able to remove my water pump without removing the harmonic balancer by removing the pump with the housing attached. I can not figure out how to detach the pump from the housing! Anyone have any advice?

Once the pump is off by itself, I was going to attempt rebuilding it myself. I have done similar rebuilds before, though I am sure this will be the most delicate and difficult. If I can figure out how to do it and where to source the parts needed, I will share all of that info.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: jllgd on 07 October 2019, 01:40 AM
Just found this vendor that seems to do 6.9 water pump repairs.
Based in Oregon.
Anyone here that have experience with them?

eBay link:
https://www.ebay.com/itm/1975-80-450-SL-SEL-6-9L-M100-Mercedes-Benz-Water-Pump-REPAIRING-Service-fix/362621699036?epid=1533929479&hash=item546df003dc:g:y6sAAOSwvzRXxM0p#viTabs_0
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: TJ 450 on 07 October 2019, 06:49 PM
Not sure about this eBay unit, it looks to be a different seller to previous ones. I have noticed Star Motors NY have the 6.3 pump listed. It would be worth enquiry as the price is good. https://www.ebay.com/itm/water-pump-for-Mercedes-300SEL-6-3-M100/302483228165?epid=16006939507&hash=item466d67c605:g:3SoAAOSwVgtZ3Ma7 (https://www.ebay.com/itm/water-pump-for-Mercedes-300SEL-6-3-M100/302483228165?epid=16006939507&hash=item466d67c605:g:3SoAAOSwVgtZ3Ma7)
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: oversize on 10 October 2019, 11:27 PM
Pumps are a common problem on the Benzes and it's mad parts are NLA for the M100.  Without going through the whole process which has been documented elsewhere, can the shaft be pressed out of the housing from the front, without having to remove the impeller?

If all else fails I'll have to get a new impeller made by CNC machine.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: TJ 450 on 11 October 2019, 01:49 AM
Nah, you've got to take the whole thing off and press it off from the impeller end (pull the impeller). It's definitely best left to someone who has done it before to save a lot of headaches.

Tim
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: jllgd on 12 October 2019, 03:26 PM
I wonder how Mercedes Benz does the core overhaul, when there are no pump parts available? Shaft, mech seal, impeller, bearing etc.
Do you guys think it's wise to keep the core and not hand it over to Mercedes Benz?
Thanks
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: arcijack on 12 October 2019, 08:51 PM
 i purchased a rebuilt pump from a fella on Ebay, has done real well with no issues, i replaced the pump myself was fairly easy i know for a fact i did not remove balancer
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: TJ 450 on 14 October 2019, 02:53 PM
Arcijack,

Was that the square base pump?

Regards,
Tim
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: arcijack on 14 October 2019, 08:16 PM
yes
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: PosedgeClk on 11 April 2020, 09:14 PM
Does anyone have a picture of the impeller? I found a parts kit for a pump rebuild for a 6.3. I am guessing that the 6.9 pumps are quite similar.

https://www.authenticclassics.com/Water-Pump-Repair-Kit-for-Mercedes-600-M100-p/auth-008776.htm

If the impellers look like the one in the photo--essentially a disc with a boss in the middle and fins protruding from the boss to the edge of the disc--this would be an easy job for a three-axis CNC machine. I have access to a Sabre 500 that needs a new controller and a lot of work to the toolchanger, but I could machine a batch of them out of 304 stainless. It might run a few hundred dollars apiece for me to break even, but it would be nice to put something out there. Stainless is a little on the brittle side, but it is nothing like cast iron.

Thoughts?
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: TJ 450 on 12 April 2020, 12:23 AM
The design of the impeller is very similar, the 6.9 one is slightly different though in profile.

I have heard of people interchanging them but have not seen it confirmed.

Certainly a very good idea though.

Posting pics is in the too hard basket now though as I'm using a phone.

Tim
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: john erbe on 14 April 2020, 02:09 PM
Careful with these alleged rebuilders. Sent mine down to one in LA. Claimed that the bearing (size) was NLA. Did some machine work and put in another common and available size. Wrong. Engine ran hotter than with original. Should any rebuilder state the same, avoid at all cost.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: PosedgeClk on 15 April 2020, 12:42 PM
Do you have any more information on what he did or just that he changed with non-OE parts? If the width and OD of the bearing are the same and the shaft is machined for a bearing with a different ID, and if the shaft can handle the load, it should be a non-issue. I am not doubting you but would like to have as many details as I can get.

I am going to be bringing a Hardinge NC lathe up and running in the upcoming weeks, so that opens some opportunities for a new shaft design. I need to take the pump off my 6.9. I was going to take a good look at it over the weekend, but there were strong storms which prohibited much progress from being made.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: Randys01 on 16 April 2020, 02:20 AM
I researched this topic deeply some years ago and culminated in me designing a new shaft and bearing assy. ..it works a treat. I am convinced that anyone offering an overhaul repair service resorted to the same thing I had to......the original bearing cannister is no longer available so rebuilders have had to come up with  something else.  It's not rocket science but I can see that hereonin, getting the vane impellor is going to be the show stopper.  As highlighted the 600/6.3 is just different enuff to hose down the obvious interchangeable unit hope. So some one with the smarts and means to recreate a 6.9 impellor is on a winner.
I will buy 2.!
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: john erbe on 20 April 2020, 01:10 PM
This took place several years back and if I recall my trusty mechanic, after describing the higher temps. told me that as a result of a different size bearing the impeller was now shifted to the wrong place.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: TJ 450 on 21 April 2020, 12:46 AM
It might be worth measuring up an M117 impeller for comparison as it looks to be a similar profile to the 6.9 one.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: PosedgeClk on 21 April 2020, 10:25 AM
Thanks, John. Thanks, TJ.

TJ, do you have a part number or photo of the M117 impeller that you are referring to?

As for John's input, that does not surprise me at all that the performance of the pump changed when the impeller's location was changed. You can't change a single thing in one of these designs without likely affecting the performance. If I make an impeller out of billet 304, the vane contours are going to be very close to those of the original casting. I would go so far as to 3D printing a negative of the part to fit into an original part to check that my model is right.
Title: Re: Mercedes 6.9: Water Pump Overhaul
Post by: Randys01 on 23 April 2020, 01:44 AM
If you refer to the Tech Library, you will see a spec for the impellor clearance on the 6.9 water pump and that is the key ...........