Author Topic: Mercedes 6.9: Water Pump Overhaul  (Read 461 times)

jllgd

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Mercedes 6.9: Water Pump Overhaul
« on: 03 October 2019, 02:28 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

UTn_boy

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #1 on: 03 October 2019, 07:10 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. 
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex
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TJ 450

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #2 on: 03 October 2019, 08:45 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
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
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raueda1

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #3 on: 03 October 2019, 09:13 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.
-Dave
Now:  '76 6.9 Euro
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

Randys01

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #4 on: 04 October 2019, 02:08 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.

PosedgeClk

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #5 on: 04 October 2019, 07:44 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.
1979 450SEL 6.9

daantjie

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jllgd

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #7 on: 04 October 2019, 05:03 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

UTn_boy

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #8 on: 04 October 2019, 08:40 PM »
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/ 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. 

1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex
1978 450sel 6.9 Euro, Anthr/velour

Harv

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #9 on: 04 October 2019, 09:07 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.
1980 300SD
1983 240D
2000 E55 AMG

UTn_boy

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #10 on: 05 October 2019, 10:45 AM »
-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? 
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex
1978 450sel 6.9 Euro, Anthr/velour

Harv

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #11 on: 05 October 2019, 05:58 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.
1980 300SD
1983 240D
2000 E55 AMG

Randys01

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #12 on: 06 October 2019, 12:53 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....

PosedgeClk

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #13 on: 06 October 2019, 01:16 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.
1979 450SEL 6.9

UTn_boy

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Re: Mercedes 6.9: Water Pump Overhaul
« Reply #14 on: 06 October 2019, 01:32 PM »
"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! :) 
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex
1978 450sel 6.9 Euro, Anthr/velour