Changing C4500 Fuel Pump

[FPRA]

Truck ran out of fuel, with almost full tank. I assume the front fuel pump needs changing. What's involved? The truck is in my yard where I can work on it (for once) forklift available if the tank needs to come out.

[Duramaster]

I need more info before I can help you with this. THis truck has two tanks? And they are factory fuel tanks, not aftermarket tanks? If the front tank is out of fuel, then the transfer pump has not transfereed fuel from the rear tank to the front tank. The transfer pump is mounted on the left rear of the frame rail (inner) just ahead of the rear tank.

How do you know the truck ran out of fuel?

[FPRA]

OK, truck is a 2003, two factory tanks, fuel filter empty. Both tanks filled 75 miles ago, guage reads near full. 83,000 miles. Just a guess on my part, but I was thinking fuel pump to filter was down. Is there something else that it could be?

[Duramaster]

There are only two fuel pumps on your truck, the rear tank transfer pump and the high pressure fuel pump in the valley of the engine. Did your truck die after started or did it die while driving? Have you tried to prime the fuel filter? Pump the primer pump ontop onf the fuel filter housing about twenty times, slowly open the bleed screw on top of the filter housing to let the air out. Reinstall the bleed screw and pump again. Repeat until there is no more air. Close the screw carefully and then try to start. It may take two or three start attempts to get the engine running again.

[FPRA]

Had A Chance To Work On The Truck Friday. Got The Filter Primed, No Easy Task Unless Your A Monkey. Truck Started And I Drove Several Miles With No Problem. Test Started It Yesterday And Today With No Problem. What Would Cause It To Lose Prime? Would Rather Fix It Now If Possible. Thanks

[Duramaster]

There could be debris in the check valves of the filter head or the filter head itself is cracked allowing the filter head to bleed off. The filter head can be disassembled down to the check valves. The valves don't appear to be removable, but you can at least see if there is any debris in the valves.

[FPRA]

Happened again. Both times in my yard. How lucky can that be. Haven't needed to use the truck, but have been starting daily to see if it would quit on me again, so maybe I can find a common denominater. One thought was possibly a pin hole leak somewhere in the line. The two times its quit so far has been right after starting, and had been sitting for 6-8 hours and one hour.Today was the one hour. Have tools need with me to bleed the filter, had it primed and running in about 10 minutes.

[FPRA]

After parking the truck for the summer, as it wasn't needed, we got back to the task to find the problem. Ended up being a pinhole leak in the top of the sending unit.Quite a lot of corrosion so we elected to replace the entire line. Would never have been able to replace the in-line pump for the rear tank without changing lines anyways.