Injector Pump Fuel Leak

[Bill Vensel]

This is my first post, and first of all, a big THANK YOU to you all for the great education you've provided.  I've been reading and searching the forum and tech notes,  and have found ideas, solutions and approaches to a variety of mechanical and electrical problems. So thank you to you all.

I resolved an issue that I did not see discussed, so thought I'd share here. Namaste has an M25XP.  I noticed fuel seeping out of the top of my injector pump. The high pressure fuel lines to the injectors connect to a part identified in the tech manual as the "delivery valve holder." It is a bolt like item that screws into the pump housing. It is hollow with a spring inside, the "delivery valve spring." No matter how hard I tightened it, fuel still made its way through the threads. On disassembly I found an o-ring at the top of the threads on each holder. It appeared that these rings had failed, and thus the leaks. I couldn't find any info on the rings, no part number or even size, but I found that a 9/16" ring fit perfectly. I replaced the rings on all three holders, reassembled, and no more leak. 

The tech manual did not show the rings, and I found them kind of by accident. Now it seems like a simple and obvious solution, but this amateur mechanic was stumped for a while. So I offer this for other amateur mechanics who might have a similar problem.

[britinusa]

Do you have any more info on the o-ring? Might be a good item to keep in the Engine Spares Box.

Paul

[Bill Vensel]

I wasn't sure of the size before disassembly, and so I bought a package of a variety of sizes at West Marine, then matched up to the old ones. Turns out the 9/16" was the best match. So now I have a bunch of o-rings, some larger and some smaller in my locker. The pack was about $8.00, but I figured it not a bad idea to have some on hand.

Bill
C34 #980, Namaste
Charlotte Harbor, FL

[Ron Hill]

Bill : Go to a place where they repairs diesel injectors and injection pumps. 

I'm sure that the "O" ring is metric!!

A thought

[Bill Vensel]

Thanks, Ron. I'm sure you are right. I was using my metric wrenches for the job. A conversion chart shows the equivalent to be about 14 or 15 mm.

[Switchback]

Any idea what the torque is on those delivery valve holders? I also need to change out those o-rings and am afraid of over tightening!

[Ron Hill]

Switch : I gave away my shop manual on the M25Xp when I changed engines. 

I'd use a spark plug torque of 15-18 Foot Pounds.  That's snug - you can tighten more if you see fit!!

A thought

[Switchback]

Thanks Ron! :)

[Ron Hill]

Guys : I was in Auto Zone and found that they have both ASE and Metric assorted "O" rings is small boxes.  Other auto supply store might also have them!!

A thought