Cummins Lift Pump

[BennieH]

Found I had the dreaded leaking lift pump on my ISC350. Tightening the bolts did not work, so I went and picked up a new lift pump from the Coach Care center. This is the new style pump since the original is discontinued. One of the mechanics there told me that it was designed to be universal in application and the bracket/top had additional places for fittings. They also changed the fuel inlet and outlet holes to make more gasket surface. You also need to get 2 plugs for it to close the unused holes. I also got a gasket for the new pump as a spare.

Saturday I went to swap it out. Holy cow is that thing in a miserable spot! Raised her with the levelers and then cribbed it with 4x4's. Dropped the starter so I could get at everything since I couldn't get at a lot for the top.

I had one of the fuel lines that would not come loose (fitting kept turning in the pump housing) and was having a devil of a time trying to get at the top lines. Finally decided to drop just the pump and look at the gasket and assess the situation. I finally went to NAPA and got sheet gasket compatible with diesel. I cut a new gasket, put it all together, cleaned all of the fuel off everything and cycled the pump 5 times without starting the coach. Perfectly dry! Took it for an hour drive on the interstate. Same results!

If it need the new pump in the future, I'll let the coach care center do it or I'll build an adapter plate that allows me to use the new pump on the old bracket.  That would not be too hard to do since I have the old pump gasket and the new spare. There is a difference in the inlet and outlet hole sizes (smaller) and all the mounting holes are the same.

[jleamont]

BennieH, the replacement pump has been redesigned so many times I would take the coach to where you bought the pump and have them install it. When it fails (not if but when) it will most likely take out the fuel injection pump which will set you back several thousand dollars.

When I replaced mine in 14' all of the access was from the top through the bedroom floor or closet floor access. You have other options that will not require you to do anything back at the original pump location other than connecting a plug into the existing harness, here's the link;