Community Forums

Doug-Terrie · 08-10-2018, 05:10 AM

Hello Everyone. My name is Doug and I recently purchased a 2000 Monaco diplomat with a 315 8.3 Cummins. I have diesel fuel dripping from The lift pump. I have been busy fixing, caulking, replacing floor, carpet etc. and have yet to tackle the lift pump. I am pretty handy with tools and restoring old Volkswagens, working on my daily drivers etc. What do I need to know to replace this lift pump? I have a full tank of fuel. When I remove the lift pump, will fuel come out?
Appears to be fairly accessible. There seems to be a wire connection that could be unscrewed and removed to gain better access. The truck repair place will not give me a solid estimate and claims could be as many as six or eight hours to repair, plus parts. I generally do all of my own repairs, but I don’t want to mess this up.

I will have to return to work in a couple of weeks, (I am at school teacher) And would like to get at least one little trip in before school starts up again. How awful is it to run with this drip? I don’t want to get stranded, and I don’t want to damage my engine. I would like to drive it about a thousand miles, ( Tennessee and back ) and then affect repairs after school starts.

Advice please.

sandwip · 08-10-2018, 09:23 AM

Doug
Do not run with a leak in your lift pump as it will draw in air as you drive and can damage your injection pump. Several people have upgraded to separate full time supply pumps to avoid this common failure. Sounds like you should be able to handle this yourself. Good luck with the repairs.

dons2346 · 08-10-2018, 09:55 AM

There is one gasket in the entire lift pump. There are bolts than hold the motor portion to the pump Some people have had luck stopping the drip simply by tightening those bolts. Here is the cheap gasket that leaks. Cummins says no gaskets available but people have found them on eBay.

followingsea · 08-10-2018, 10:21 AM

Quote:

Originally Posted by sandwip

Doug
Do not run with a leak in your lift pump as it will draw in air as you drive and can damage your injection pump.

Good advice!

Here is my post: http://www.irv2.com/forums/f123/isb-...ml#post4195509

There are other lift pump posts and you want to make sure about things for your engine.

General advice, 4 hands are better than 2. It is a messy job. It is important to get the pump filled and vented.

Ivylog · 08-10-2018, 03:26 PM

Try tightening the 3 small bolts from the bottom. May be 10mm.

Doug-Terrie · 08-10-2018, 08:18 PM

Thanks all. I will tackle this in the coming days. I will post my results. Thank you again.

funjnt · 08-11-2018, 04:42 AM

I replaced the lift pump in our 99 Allure. I didn't try to fix the leak which I didn't know at the time was an available or semi available gasket. It is a project you can do but there is one catch. You will need a fairly large allen wrench to take the plugs out of the old pump and re install into the new pump. They are just blanks to cover the unused openings with o rings. I don't know the size of the wrench but it is like 1/2 inch. If you get pump out first thing in am you could take it to parts story or a shop maybe and borrow a wrench and switch them around. Other than that it is pretty easy. Well you may have to be a little of a contortionist to get under bed or to pump. Good luck.

Ivylog · 08-11-2018, 06:35 AM

Someone posted recently a non Cummins source for just the gasket...do a search.

mwallin · 08-11-2018, 05:34 PM

GET IT FIXED ASAP mine was doing the same and I let it go only to have a $1400 tow bill and a $8600 freightliner bill

Ray,IN · 08-11-2018, 09:05 PM

Quote:

Originally Posted by Doug-Terrie

Thanks all. I will tackle this in the coming days. I will post my results. Thank you again.

Observe torque values for the bolts. I've read prior threads about loosened bolts, and re-torquing stopped the leak.

Skip426 · 08-11-2018, 10:52 PM

This is an old pdf so I can't say if the number listed is still good .

The original gaskets didn't do well with ultra low sulfur diesel fuel.

Diagram is of the lift pump and the fuel manifold.

EDIT: I found this in my notes , hope it helps ; post #4 has a link.

http://www.irv2.com/forums/f123/isc-...on-353936.html

John Jones · 08-11-2018, 10:57 PM

If your engine is easily accessible and even if you have limited mechanical ability, then you can do this. I did mine for the first time in about 3 hours. Simple job, no special tools other than a large allen

Ivylog · 08-12-2018, 03:04 AM

Now that I'm on a computer I found where you can still buy just the gasket posted by Cewarre who has a 2002 ISC engine. Around 2004 the gasket changed slightly to where you have to change the entire housing and pump, not just the gasket or just the pump off of a newer lift pump assembly ($450). Cummins told me I could do that on my 03 ISL...NOT.

"I spoke with Carl at Capital Volvo, 1-800-247-5673 and he said he still has 370 of the aftermarket gaskets in stock for the Cummins lift pumps and gets calls quite often. They are still $6.71 each and he is shipping me two via UPS. He said the aftermarket gaskets reference to Cummins part numbers 3964385 and 4935004."

While these #s do not match the Cummins link above it would be worth hundreds of dollars in labor to be able to just change the gasket...a much easier job. If you have to change the entire lift pump, do not tighten the mounting bolts (Pump and housing to engine) until you get all of the lines reattached/started and then tighten to the engine...took an hour trying to get one line started before loosing the housing from the engine.

BigLar368 · 08-12-2018, 07:26 AM

I did not change mine but I had to get to it to make some changes as I went to a full time FASS pump. Taking the starter off and getting it out of the way made things much easier to get to.