300D IP leak... how to fix? - PeachParts Mercedes-Benz Forum

greg273 · #1 10-14-2007, 03:17 PM

Is there any sort of washer or O-ring at the injection pump, where the metal lines go into the top of the pump body itself? The location with the 2 bolts (13mm, I believe...). This is from a 75 300D.

I am getting a pretty drastic leak at that area, where the threaded part meets the pump housing itself.

Is there a washer, or is this a compression type fitting?

Anyone know the torque specs on that? From an archived thread, I see 30NM is recommened on a later model.

thanks,
Greg

#2 10-14-2007, 03:28 PM

There is a copper crush washer under the fitting. DO NOT touch the two 13mm nuts for any reason.

greg273 · #3 10-14-2007, 09:44 PM

Ok, then how to stop the leak? Re-torque the threaded fitting? Replace washer?

300SDog · #4 10-14-2007, 10:36 PM

Greg, how sure are you it aint the inj pipe fitting thats leaking? Seen this myself on 240D where hairline crack develop in the plumbing underneath the collar nut.

greg273 · #5 10-15-2007, 03:19 PM

I'm pretty certain the leak is coming from the top of the IP itself, around the threaded part (delivery valve?) below the metal lines. This is my first working mercedes so I am quite lost, and dont want to destroy it, or make things worse by overtorquing something on the IP.
I have sent for a manual for this car, so until that arrives I am pretty much in the dark here.

winmutt · #6 10-15-2007, 03:31 PM

There is a DIY around here on it but I cant seem to find it.

greg273 · #7 10-19-2007, 11:46 AM

I received the W-114-115 Factory Service Manual today (on cd rom), and it was no help in showing the IP components.
Anyone know where I can find a diagram of the injection pump? What could be causing a leak at that point, other than a leaking connection? Something internal causing abnormal pressure to build?
So dont touch the 13mm bolts, got that.

300SDog · #8 10-19-2007, 04:00 PM

How bout wrapping threads with plumber's tape?

Stevo · #9 10-19-2007, 08:09 PM

There is a copper delivery valve "seal", which is the "lower" most item you can remove from the hole when you remove the delivery valve (15mm), dont touch the two nuts on either side of the delivery valve. There is a spring, a little pointy gizmo and a "fat" washer, then the seal. When these fail your delivery valves leak around the threads. I replace them one at a time when they start to leak. Be careful to keep things very clean. This is on my W123s and I think yours is the same.

NC300SDL · #10 10-19-2007, 08:41 PM

Do a search for injection pump leak. You will find detailed instructions if you look long enough. Yes, there are rubber seals under the injection nozzles. I had same problem with my 300 sdl. Special splined socket required to remove nozzles. Not too bad of a job. I replaced mine and have not had any more leaks. You might also have a hairline crack in one of the fuel lines. Or if like mine, the nipple, that seats in the injection nozzle, was completly broken off the line.

bgkast · #11 10-20-2007, 01:58 PM

Quote:

Originally Posted by NC300SDL

Yes, there are rubber seals under the injection nozzles. I had same problem with my 300 sdl.

Not on the 617 AFAIK.

Stevo · #12 10-20-2007, 06:54 PM

Quote:

Originally Posted by bgkast

Not on the 617 AFAIK.

My "85" Euro 240D has the M/RSF "IP" (vacuum shut off on top, splinned delivery valves) thats the type that has the rubber O ring. Most 616/617 have the MW IP with mechanical governor. His is a 76 300 so I assumed (yah, I know what they say

) his was the MW type which are a piece of cake to replace the single copper seals on. Anyway this is how I understand it.

bgkast · #13 10-20-2007, 08:48 PM

Quote:

Originally Posted by Stevo

My "85" Euro 240D has the M/RSF "IP" (vacuum shut off on top, splinned delivery valves) thats the type that has the rubber O ring.

Interesting. I did not know the Euro M pumps had rubber O rings.

Stevo · #14 10-20-2007, 08:59 PM

Quote:

Originally Posted by bgkast

Interesting. I did not know the Euro M pumps had rubber O rings.

Well, I don't either

, never been into that one but from the description in the manual it does, I'm not even tempted to open it up and see till I need too. I do know that the IPs on the US spic W123, 240Ds just have copper sealing rings. As too his "76".......

Maybe I made a wrong assumption.