3B Rotary Injection Pump leak

Aug 11, 2008
Okanagan Valley, B.C.
My 87' BJ70 sits a lot since I only use it in the fall months. Recently I noticed some diesel leakage underneath the truck. The top of the IP looks dry but from underneath the truck I can see that there is a plate on the side of the IP that is covered. From what I've read on previous threads this must be the IP timing cover plate and that there are a couple o-rings beneath it that require replacing. My question is how easy is the plate to remove and is there anything I need to be aware of while replacing the o-rings? I don't have too much experience working on the IP and don't want to misadjust anything. Thanks.





2LTE abuser
Mar 23, 2012
Victoria, BC, Canada
These leaks are common on the rotary injection pumps of this vintage. I've re-sealed a couple of them now (a mechanical 2LT-II and a 2LTE one). Seal kits are about $40 on ebay or so. I bought from a UK seller who was quite helpful.

You could try to fix just the leaks you see with the pump on the engine. But it would probably be best to remove the pump from the engine completely, clean it, and reseal the whole thing.

If you have lots of wrenching experience, it's not that bad. If you don't have much experience, you might be best off paying a knowledgeable diesel shop to do the job for you.

One of the big tricks is replacing the seal on the pump head. You don't want to completely remove the head or your pump will fall apart inside. It's possible just to lift it a bit and slip the seal over the pump head. If you take the job on I'll explain this in more detail later.

Also, when you re-install the pump you'll need to use a dial gauge setup to set the injection timing properly.

Download the manual for the 3B-II and do some reading to get an idea of what all is involved....
Last edited:

Hugh Heifer

Chasing the Beast
May 10, 2006
Rome, GA
Mine leaked a number of years ago. I had a Mercedes shop fix it but I had to source the parts. I have wrenched on many things but that pump untimidated me. Has been fine for 6 years.

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