Leaking Plunger, mech lift pump 6bta M3 CPL2008

[paul greenhalgh]

The plunger on my Bosch P-7100 mech lift pump leaks when I use it…but it does pump fuel and doesn’t leak when engine is operating. I have removed the plunger assembly (see pics attached) but I cannot figure out how to disassemble to check for an O-ring that I’m guessing needs replacement.

Can anyone tell me the part number for the plunger assembly (not the whole mechanical pump) and/or provide an exploded parts diagram for the plunger and/or tell me how to get the thing apart?

Thanks in advance

Topic

[Rob Schepis]

Great, thanks for the follow-up Paul. If you took any photos during the install please post them.

[Paul Greenhalgh]

Source Found for Hand Primer

Following Tony’s advice above that the hand priming pump is a Bosch component, not Cummins, I searched on-line and pretty quickly discovered there are both Bosch original and Chinese knock-offs of these priming pumps readily available. The Bosch original is only around $20 on ebay…so why would you bother with a copy?

These priming pumps are sealed units and not repairable.

Attached pic shows both the box and part number that my replacement came in and the pump itself. It is supplied with a copper washer.
Removing the old/installing the new is a fiddly job. Best to dis-mount the throttle cable bracket aft of the pump that gets in the way, but even so you will need a small-ish 17mm spanner or a very small adjustable wrench. The body of the pump is a soft aluminium so go easy.

With the old pump removed, I saw a copper “washer” in the throat of the P7100 itself. Thinking this was the copper washer from the hand pump, I tried without success to pick it out. I couldn’t, so I don’t know if it was just crushed in place or a copper mounting surface to match the new washer. In any event, I used the new copper washer supplied with the pump and tightened all up gently. No leaks after a long run and the new pump works fine. I have ordered a 2nd priming pump to preventatively swap out the one on the other engine of my twins.

Hope this helps others: there have been several posts about leaking priming pumps over the last few years, with no-one reporting if/how they eventually fixed the problem.

[Rob Schepis]

Paul,
I noticed a recent reply from you on this on the home screen but it is not here? Maybe you posted and then deleted, not sure… Can you post again. This could be a helpful thread and find. Thanks.

1 user thanked author for this post.

Paul Greenhalgh

[Paul Greenhalgh]

Following Tony’s advice above that the hand priming pump is a Bosch component, not Cummins, I searched on-line and pretty quickly discovered there are both Bosch original and Chinese knock-offs of these priming pumps readily available. The Bosch original is only around $20 on ebay…so why would you bother with a copy?
These priming pumps are sealed units and not repairable.
Attached pics show both the box and part number that my replacement came in and the pump itself. It is supplied with a copper washer.
Removing the old/installing the new is a fiddly job. Best to dis-mount the throttle cable bracket aft of the pump that gets in the way, but even so you will need a small-ish 17mm spanner or a very small adjustable wrench. The body of the pump is a soft aluminium so go easy. With the old pump removed, I saw a copper “washer” in the throat of the P7100 itself. Thinking this was the copper washer from the hand pump, I tried without success to pick it out. I couldn’t, so I don’t know if it was just crushed in place or a copper mounting surface to match the new washer. In any event, I used the new copper washer and tightened all up gently. No leaks after a long run and the new pump works fine. I have ordered a 2nd priming pump to preventatively swap out the one on the other engine of my twins.
Hope this helps others: there have been several posts about leaking priming pumps over the last few years, with no-one reporting if/how they eventually fixed the problem.

[Paul Greenhalgh]

Following Tony’s advice above that the hand priming pump is a Bosch component, not Cummins, I searched on-line and pretty quickly discovered there are both Bosch original and Chinese knock-offs of these priming pumps readily available. The Bosch original is only around $20 on ebay…so why would you bother with a copy?
These priming pumps are sealed units and not repairable.
Attached pics show both the box and part number that my replacement came in and the pump itself. It is supplied with a copper washer.
Removing the old/installing the new is a fiddly job. Best to dis-mount the throttle cable bracket aft of the pump that gets in the way, but even so you will need a small-ish 17mm spanner or a very small adjustable wrench. The body of the pump is a soft aluminium so go easy. With the old pump removed, I saw a copper “washer” in the throat of the P7100 itself. Thinking this was the copper washer from the hand pump, I tried without success to pick it out. I couldn’t, so I don’t know if it was just crushed in place or a copper mounting surface to match the new washer. In any event, I used the new copper washer and tightened all up gently. No leaks after a long run and the new pump works fine. I have ordered a 2nd priming pump to preventatively swap out the one on the other engine of my twins.
Hope this helps others: there have been several posts about leaking priming pumps over the last few years, with no-one reporting if/how they eventually fixed the problem.

[Tony Athens]

You need to hook up with a Bosch certified injection pump shop OR start searching through GOOGLE , and maybe even Cummins truck forums for aftermarket parts-The Cummins factory parts system will not offer an solution..

[Author]

Replies