The fuel pump failed in my 91 C2500 work truck a short time ago. I thought I'd add my notes on the replacement.
The diagnosis was pretty simple. Truck fired with starting fluid, and the fuel pump relay output was good.
I found pretty much all the information needed in a variety of places, and this will be the third fuel pump I've replaced in the GMT400 series, so the only obstacle was overcoming the "what a pain" attitude.
Previously I'd dropped the tank, so for a change I tilted the bed.
Locate and remove the eight bed bolts. These take an 18mm socket. They are installed with threadlocker, so will be tough to turn out. I used an 18" breaker bar, ratchet, extensions and a u-joint. I removed four step bumper bolts to give room for the rearmost two bed bolts.
Remove the three screws holding filler neck flange to bed. These took a Torx T30.
Remove the ground screw connecting the bed to a metal fuel pipe. Not sure what that pipe is; vapor, overflow, ?
Remove the ground screw at the rear connecting the bed to wiring harness.
Disconnect right rear light harness plug.
At this point, the bed is ready to lift. I used a hoist with hooks under the wheel well. Cardboard between the hooks and bed to protect the bed. Also, some OSB scrap between the cab and bed.
Once high enough, bed is blocked up with scraps of wood. The hoist is still in place.
Now you have access to the tank, fuel pump and the fuel lines. I removed the filler neck assembly completely to give me more room and stuffed a rag in the fuel tank opening to keep whatever out.
Disconnect the threaded connections, and the single rubber clamped hose. I believe I used a 5/8" and a 3/4" wrench on each threaded connection. They came apart easily oddly enough. There was some fuel in one line, which I belatedly caught in a handy cake pan.
The fuel pump retaining ring is tapped counterclockwise to release the pump. Hammer and metal drift used here. Again, little resistance and it came loose easily.
So, remove the pump using whatever maneuvers are needed to get the sock filter, float, etc out.
I did test the pump once removed. It was dead. No motion, no noise, no smoke, nothing.
Now time to put in the replacement. Next ...
The diagnosis was pretty simple. Truck fired with starting fluid, and the fuel pump relay output was good.
I found pretty much all the information needed in a variety of places, and this will be the third fuel pump I've replaced in the GMT400 series, so the only obstacle was overcoming the "what a pain" attitude.
Previously I'd dropped the tank, so for a change I tilted the bed.
Locate and remove the eight bed bolts. These take an 18mm socket. They are installed with threadlocker, so will be tough to turn out. I used an 18" breaker bar, ratchet, extensions and a u-joint. I removed four step bumper bolts to give room for the rearmost two bed bolts.
Remove the three screws holding filler neck flange to bed. These took a Torx T30.
Remove the ground screw connecting the bed to a metal fuel pipe. Not sure what that pipe is; vapor, overflow, ?
Remove the ground screw at the rear connecting the bed to wiring harness.
Disconnect right rear light harness plug.
At this point, the bed is ready to lift. I used a hoist with hooks under the wheel well. Cardboard between the hooks and bed to protect the bed. Also, some OSB scrap between the cab and bed.
Once high enough, bed is blocked up with scraps of wood. The hoist is still in place.
Now you have access to the tank, fuel pump and the fuel lines. I removed the filler neck assembly completely to give me more room and stuffed a rag in the fuel tank opening to keep whatever out.
Disconnect the threaded connections, and the single rubber clamped hose. I believe I used a 5/8" and a 3/4" wrench on each threaded connection. They came apart easily oddly enough. There was some fuel in one line, which I belatedly caught in a handy cake pan.
The fuel pump retaining ring is tapped counterclockwise to release the pump. Hammer and metal drift used here. Again, little resistance and it came loose easily.
So, remove the pump using whatever maneuvers are needed to get the sock filter, float, etc out.
I did test the pump once removed. It was dead. No motion, no noise, no smoke, nothing.
Now time to put in the replacement. Next ...
