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crah 02-22-2016 02:12 PM

Cummins ISC lift pump replacement
Well I've been hit with the dreaded lift pump leaking. I have a 2003 Holiday Rambler coach on a 2002 Roadmaster chassis with a cummins ISC 350. The pump was quite hard to access with some wiring looms in the way. I searched the forum and found that tightening the bolts sometimes does the trick. My bolts were all tight so looks like I need a replacement. Anyone have a part number and source to get these pumps from? Any pointers on the replacement? Looks like 4 mounting bolts and I couldn't really see the other connections well. I'm sure there is a fuel input/output and maybe a wiring harness?

jacwjames 02-22-2016 08:44 PM

I don't have a leak but have been doing some research in preparation in the event I get one.

If you haven't already join the Cummins Quickserve site, once you register out in you engine serial number. it will bring up some screens, go the parts, fuel systems, Accessories, Fuel transfer pump. It will give you the appropriate part number.

Cummins has changed the part several times so using the Quickserve site will give you the right one.

My part number is 4935005 and will cost ~$375 depending on where you get it. This is the complete assembly including the mount.

Back in the mid 2000's after the ULSD was put on the market there was a rash of fuel pump failures. The low sulfur fuel would cause a gasket failure in the fuel transfer pump. Cummins put out a bulletin instructing service shops to replace the gasket however they stopped doing this as a gasket cost $7 with 1/2 hour of labor versus the new transfer pump.

I found my gasket number is 4928511 and am searching for a place to buy it, found one place that I will confirm this week. I intend to buy a gasket to have as spare.

Keep us posted on your fix

CountryFit 02-22-2016 08:55 PM

can you look at where the leak is at? you might need a mirror or video camera to see it. most likely the leak is from the gasket between the pump and the mounting bracket. i remember there are 3 bolts holding the pump, if those are very right as you said, chances are the gasket is torn. get that replaced, you might resolve the problem.

John Jones 02-22-2016 09:43 PM

Keep us posted on where to buy the gasket. I might get a couple for myself!

AFChap 02-23-2016 09:29 AM

I had a Cummins SE location replace mine. They did it from the top via the under the bed/closet access holes.

crah 02-23-2016 10:28 PM

Thanks all for the info. I will order a new pump this week sometime and hopefully get it changed out soon.

jacwjames 02-24-2016 10:08 AM

I just placed an order for the gasket, I ordered it from

Phone # 1-800-247-5673
Clarence Henley
Capital Volvo Trucks & Mitsubishi
Capital Trailer & Equipment Co., Inc.
Capital Exports of the US

Price was $6.71 plus shipping, he was going to try and ship it USPS instead of UPS.

This is not a OEM part but aftermarket gasket. I don't think Cummins even sells this part.

Here is a link to the service bulletin,
I searched the Quickserve site and this bulletin isn't even available anymore. It lists 2 different gaskets but the Capital Volvo shop said the 2 numbers interchange.

I have ordered one of the gaskets and will keep it as a spare just in case. I plan to check the transfer pump on a regular basis for leaks.

Dave Fernandez 02-24-2016 02:05 PM

I replaced my lift pump last year on 2001 Alpine 38ft MH. Because of the island bed the procedure was not to difficult. It took me 4 hours because it was over 100 outside and humid. Because I was working on the engine with the cover open for access I was stuck with heat and humidity. If I had only replaced the gasket and it did not work I would have been real mad. Just because all the work to R&R for just a gasket.

I am glad I replaced the entire pump assembly now no worries. The new pump was designed to operate with the ULSD.

I also replaced all of the O rings on the fittings with the upgraded O rings for use with ULSD.

Now I do have any worries about the pump and fittings leaking.

hypoxia 02-25-2016 08:38 AM


Originally Posted by jacwjames (Post 2951939)
This is not a OEM part but aftermarket gasket.

A bunch of folks would benefit if you show the part & packaging, manufacturer etc. when you get it. I'm curious to see if it is a paper or rubber type gasket.

Coma 02-26-2016 02:38 PM

The pump is also prone to leaking at the electrical inlet, no gasket for that. The new pump is configure differently than the old one, so you will need assorted adapters and plugs to make it work.

It was about $400 labor to have it put in.

jacwjames 02-28-2016 07:51 AM

I received the transfer pump gasket in the mail yesterday. I is packaged in a small plastic type bag and has Genuine Cummins Parts with the Cummins Insigna and is dated 9/18/06. This is close to the date range of the TSB that I found on Cummins. (note the sales person said that they had the gasket made and would be and after market part).

The gasket is made of a heavy rubber type material.

Anyway, I'm keeping the gasket just as insurance (cost $7.71 including shipping) in case I'm stuck on the side of the road. I would repair and then when I get home change out the lift pump.

Unfortunately Cummins no longer just sells the lift pump but you have to buy the entire mounting assembly for an outrageous price.

passerby 03-23-2016 08:14 PM

1 Attachment(s)
Mine to is leaking. Ordered one today. I noticed something was leaking, just tracked it down. :eek:

USMCRET 03-24-2016 06:11 AM

Where is this lift pump generally located on these engines?

passerby 03-25-2016 07:21 PM

Mine is on passenger side, halfway between top and bottom of engine. It has lots of hoses.

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