Significant diesel leak ... - PeachParts Mercedes-Benz Forum

#1 08-28-2007, 07:29 PM

Hi all:

Following the forum's suggestions from this weekend, I tracked down the correct parts & replaced the crush washers at the base of the delivery valves on top of the IP. Out of four, one had no washer at all and the others looked a bit tired.

All looked great ... sent her off this morning ... and it's leaking again tonight

. The driver is on the sofa with a "diesel headache" and a glass of wine.

I just took another look and my suspicions that one of the studs on the IP is stripped appears to be true

. I noticed the nut felt like it was "slipping" when I checked its tightness yesterday and sure enough it's not tightening down. This is on the same valve that appeared yesterday to be the leak culprit, and it now seems likely that the PO over torqued it a bit and I finished 'er off

.

With that in mind, I'm soliciting for [strong] opinions from the experienced here:

1. Aside from the crush washers, is there another likely candidate for leaks coming from the top of the IP? In an example I have from a more recent 5-banger, it appears there's an o-ring on the outside of the delivery valve "piece" (that bolts into the IP, not where the crush washer is). Does my earlier model have this?

2. Is my IP doomed because of the stripped stud or does anyone have a stripped bolt experience ... Perhaps a larger diameter stud or a steel-like epoxy? The latter is likely more easily obtained.

Many thanks in advance.
sga

nhdoc · #2 08-28-2007, 08:12 PM

Not sure what you mean by the "stud"...are you talking about the delivery valve body? The threaded part that goes into the IP or the cap that holds the hard line to it?? If the threads on the IP are stripped you may be in some trouble, but the DV itself is available as a replacement part.

#3 08-28-2007, 08:22 PM

Clarification photo of my ip. nhdoc : to clarify it's not the valve body itself, it's the stud. Perhaps it's actually sheared off; that might explain the sudden leak as well ... ?

Cervan · #4 08-28-2007, 09:05 PM

wow thats not good lol..

#5 08-28-2007, 09:44 PM

Honestly, I would bring it to a good shop and let them diagnose it.

yellowbenz · #6 08-28-2007, 10:27 PM

If I read your post correctly you replaced the copper washers but not the o rings. If so you really didn't address the source of the leak if the deliver valve seals were the problem. AFAIK that stripped stud shouldn't be as big a problem as it secures the hold down plate for the delivery valve.

Kevin
1979 240D manual
1984 300D

TMAllison · #7 08-28-2007, 11:13 PM

I'd contact a bosch service center and confirm the stud is simply a stud and if so get a replacement, pull it out and install the new one. Should be fairly easy.

What torque did you use on the delivery valves?

#8 08-29-2007, 09:40 AM

yellowbenz: That is correct, I only replaced the copper. From what I understand now though there's a rubber o ring on the outside of the whole body itself that should also be replaced.

TMAllison: Excellent suggestion about the Bosch shop. For lack of a better idea I used ~45 ft-lb (although they were on tighter). Do you know what the actual spec is on the studs and the delivery valves?

I will pull the dreaded #2 off tonight and evaluate the stud situation. It's clear that the PO messed around with this delivery valve as the nuts are slightly different than all the others...

Fingers crossed. Thanks again.

TMAllison · #9 08-29-2007, 11:16 AM

I do not know your torque but suspect that 45LBS may be high. Someone will chime in with the info. Yours will be different, but for example the 60x series has a final torque of up to 35NM (26lbs).

45lbs = 61nm

Stevo · #10 08-29-2007, 12:19 PM

Quote:

Originally Posted by yellowbenz

If I read your post correctly you replaced the copper washers but not the o rings. If so you really didn't address the source of the leak if the deliver valve seals were the problem. AFAIK that stripped stud shouldn't be as big a problem as it secures the hold down plate for the delivery valve.

Kevin
1979 240D manual
1984 300D

I believe there is NO rubber "O" ring too replace in his IP (MW pump) just the copper "sealing rings"

Stevo · #11 08-29-2007, 01:11 PM

The shop manual says, in regard to the "M" IP "Do not loosen element connection (stud thats striped) since otherwise a basic adjustment of IP on IP test bench will be required" 07.1.4-210-4. The M/RSF IP with mechanical governor has the rubber "O" rings.

#12 09-09-2007, 02:45 PM

Hi again:

My delivery valve seals arrived so, coffee in hand, I took everything apart this morning ... only to discover that the seals are incorrect.

I've attached photos of the delivery valve and its seal, which is larger than an o-ring and roughly rectangular in cross section.

I'd be greatly appreciative if someone could direct me to the correct replacement parts.

Many thanks;
sga

#13 09-09-2007, 03:31 PM

That isn't the delivery valve, that's the plunger barrel! Very bad to take it out.

You'll have to get your pump bench tuned to get it reset correctly.

TMAllison · #14 09-09-2007, 03:56 PM

And don't bother torquing it back in there either. On the 606 at least,that causes a deformation of the plunger and/or pump resulting in folks needing a new one.

Take as is to a Bosch service center.

Stevo · #15 09-09-2007, 08:23 PM

Crap, I didn't want too see that. Like I mentioned in a previous post, when you take that apart you need to have the IP re set. That plate should never touched by us mire mortals. It doesnt look like the seals are right anyway, should be copper 'crush washer" type seals.