Author Topic: Mercedes 6.9: Water Pump Overhaul  (Read 1851 times)

jllgd

  • Enthusiast
  • *
  • Posts: 39
  • Location: Harbor City, CA
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #15 on: 06 October 2019, 01:50 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.

UTn_boy

  • W116 Addict
  • ****
  • Posts: 1,236
  • Chrome Bundts & bundts with white walls are a sin!
  • Location: knoxville, tn
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #16 on: 06 October 2019, 02:38 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!  :)
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1971 280sel Black/black leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex

3l33ter

  • Enthusiast
  • *
  • Posts: 91
  • W116 Enthusiast
  • Location: San Francisco bay area
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #17 on: 06 October 2019, 04:22 PM »
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.
'75 280S
'77 6.9
'82 300TD

jllgd

  • Enthusiast
  • *
  • Posts: 39
  • Location: Harbor City, CA
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #18 on: 06 October 2019, 11:40 PM »
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

TJ 450

  • W116 Addict
  • ****
  • Posts: 4,231
  • Location: Rockingham, Western Australia
    • Tim's Insulators Downunder
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #19 on: 07 October 2019, 04:49 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
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

oversize

  • W116 Addict
  • ****
  • Posts: 1,330
  • W116 Nut
  • Location: Melbourne, Australia
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #20 on: 10 October 2019, 09:27 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.
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

TJ 450

  • W116 Addict
  • ****
  • Posts: 4,231
  • Location: Rockingham, Western Australia
    • Tim's Insulators Downunder
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #21 on: 10 October 2019, 11:49 PM »
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
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

jllgd

  • Enthusiast
  • *
  • Posts: 39
  • Location: Harbor City, CA
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #22 on: 12 October 2019, 01:26 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

arcijack

  • Classic
  • **
  • Posts: 115
  • W116 Enthusiast
  • Location: meridian, mississippi
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #23 on: 12 October 2019, 06:51 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
« Last Edit: 12 October 2019, 06:57 PM by arcijack »

TJ 450

  • W116 Addict
  • ****
  • Posts: 4,231
  • Location: Rockingham, Western Australia
    • Tim's Insulators Downunder
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #24 on: 14 October 2019, 12:53 PM »
Arcijack,

Was that the square base pump?

Regards,
Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

arcijack

  • Classic
  • **
  • Posts: 115
  • W116 Enthusiast
  • Location: meridian, mississippi
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #25 on: 14 October 2019, 06:16 PM »
yes

PosedgeClk

  • Enthusiast
  • *
  • Posts: 60
  • From Sea to Shining Sea
  • Location: Atlanta
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #26 on: 11 April 2020, 07:14 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?
1979 450SEL 6.9

TJ 450

  • W116 Addict
  • ****
  • Posts: 4,231
  • Location: Rockingham, Western Australia
    • Tim's Insulators Downunder
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #27 on: 11 April 2020, 10:23 PM »
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
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

john erbe

  • Classic
  • **
  • Posts: 100
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #28 on: 14 April 2020, 12:09 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.

PosedgeClk

  • Enthusiast
  • *
  • Posts: 60
  • From Sea to Shining Sea
  • Location: Atlanta
Re: Mercedes 6.9: Water Pump Overhaul
« Reply #29 on: 15 April 2020, 10:42 AM »
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.
1979 450SEL 6.9