Park the truck on a level surface, turn off the engine, and apply the parking brake.
Locate the fuel tank. In the 1987 GMC S15, the fuel tank is located under the bed of the truck.
Disconnect the negative terminal of the battery to disable the electrical system and reduce the risk of sparks or fire.
Chock the wheels of the truck to prevent it from rolling.
Raise the rear of the truck using a jack and jack stands. Be sure to use proper safety precautions when raising the truck.
Crawl underneath the truck and locate the fuel tank straps. These straps hold the fuel tank in place.
Loosen and remove the fuel tank straps. Be careful not to drop the fuel tank.
Lower the fuel tank carefully until it rests on the ground.
Disconnect the fuel lines and electrical connectors from the fuel tank.
Remove the fuel tank sending unit, which is located on top of the fuel tank.
The fuel pump is usually attached to the fuel tank sending unit. You can remove the fuel pump by disconnecting the electrical connector and removing the mounting bolts.
Once you have removed the fuel pump, you can inspect it for any damage or wear and replace it if necessary.
