I replaced my injectors and fuel pressure regulator yesterday, and now I have a leak that looks like it's coming from one of the delivery valves on the injection pump. It will leak both when I operate the hand primer pump, or when I crank the engine. Additionally, the fuel lines for the #1 and #2 cylinder don't seem to want to prime. Could this be related, or am I just being impatient?

The car is a Euro spec '84 300D. Attached are pictures of where the leak is coming from, as well as the model plate from the pump.

Attached Thumbnails

     

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1984 300D
Euro spec, 5 speed
217,000 miles

You have the M pump which is prone to leaking from the O-ring seals on the delivery valve holders. Poke around the forum for the procedure on how to do this job, it isn't difficult but you will need the special splined socket, a new set of O-rings, and a new set of copper crush washers.

The 60x series engines used this series of injection pump. You will have good luck finding a how-to if you look for the 602 or 603 engine.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

OK, thanks! I did some searching, and I have what are hopefully the right parts and tool ordered. Do you think the leak could be related to it not wanting to prime? It's a pretty good sized leak, I'd say several good sized drops per second fall off the IP, even just using the hand primer.

The primer pump doesn't prime the fuel lines, only the fuel rack in the injection pump. The only way to get the lines bled out is to crack the nuts loose and crank the engine once you get the rest of the system primed. Pedal to the floor when cranking greatly reduces the amount of time you spend bleeding lines. With fuel leaking out of the pump, air is leaking in to displace it. I wouldn't expect the leak to cause a lack of priming, but it can certainly cause the system to air up when sat overnight as well as wasting fuel.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

My injection pump had two of the copper crush washers under each delivery valve. Is this normal, and do I need to put two new ones in each? I only ordered 5 of the crush washers because that's all I thought I'd need.

Looks like I spoke a bit too soon. The delivery valves for cylinders 1, 4, and 5 all had two crush washers, cylinder 3 had one, and cylinder 2 had none! I'm thinking someone else has had the delivery valves off before, and either didn't know what they were doing or they weren't very careful.

Clearly a hack had been in there at some point. There should only be a single copper washer in each delivery valve holder.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Got the news seals in and the lines bled out, and with the fresh nozzles from Greazzer it runs better than ever! Thanks for the help!

please share where you bought the orings, and copper washers to do this job.

Just got done doing this job on a 1987 300sdl.

Removed the intake manifold. Take pictures so you can see where all the clips and "hangers" go when reassembling. There's alot of small parts that go back and it's hard to keep track.
Followed the instructions to torque three times and no leaks!
Just time consuming - take your time.

Ask and ye shall receive: Delivery valve internal leak as a cause of nailing? Yes? No? Maybe???

This job can be done on the OM603 without removing the intake manifold. Space is tight, but it is possible, and in my experience far preferable to taking that PITA manifold off.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I went to change my delivery valve seals, and the hex screws that hold the locking plates are frozen and are stripped! I put PB penetrating catalyst and let it sit, but no use at all. Help please! I obviously am not going to use heat near the IP. I'm afraid of ruining the threads by drilling them out.

Advice is greatly appreciated.

Thanks,
Kris

If you're talking about the Torx screws, try a set of blunt-nosed vice grips. I had a seized one on mine and the vice grips broke it loose. Make sure you have them clamped down HARD to keep from spinning. Instead of trying to torque the screw loose, give it a sharp pop with another pair of pliers or the end of a ratchet handle. Once you break torque, you should be able to back them out.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)