How to Change a Fuel Pump on a 1985 Oldmobile Cutlass

In many ways, the 1980s were just as, or perhaps more, revolutionary than any other period in automotive history. Up through the late 1970s, automotive evolution had been a fairly slow process, with the technology of each chassis and every manufacturing process built largely on those that came before. But the emissions mandates of the 1970s forced automakers to start thinking outside the box, offering technologies like electronic fuel injection, and offsetting the cost of those systems with widespread platform sharing. The Olds Cutlasses of this time period were prime examples of new-school thinking, and many of the refinements they utilized -- like in-tank fuel pumps -- would live on for decades to come.

Instructions

1

Locate the car's fuel pump fuse, and remove it. Start the car, and allow it to idle until it stalls in order to relieve all pressure in the fuel system. Replace the the fuse, and disconnect the negative battery cable. Kick chocks both behind and ahead of the front wheels. Raise the rear of the car, and place jack stands under the jack pads just ahead of the rear wheels. Slide your floor jack under the fuel tank, and raise it till it comes into contact with the tank.

2

Remove the bolts that secure the fuel tank straps to the car's frame. Have your assistant steady the fuel tank as you lower the jack. Hopefully, you thought ahead and ran the car nearly out of gas before replacing the fuel pump; a full gas tank can weigh 100 pounds or more, and an empty tank less than 20. Obviously, you'll find this much easier and safer with an empty tank.

3

Reach over the gas tank, and unplug the electrical harness connectors. Remove the fuel lines, and very carefully lower the tank to the ground. Slide it out from under the car to access the fuel pump in the top of the tank. You'll see the locking ring encircling the pump. Wrap the tip of a large flathead screwdriver with a rag -- to prevent sparks -- and place the tip against one of the tabs on the ring. Tap the screwdriver with your mallet to turn the ring counter-clockwise and release the pump. Pull the pump assembly out.

4

Release the clamp that secures the fuel pump the the fuel pump assembly; replace the old fuel pump with the new one, and tighten the clamp. Make sure that the hose isn't deteriorated, and check the "sock" filter for signs of clogging damage or deterioration; replace as necessary. Once you have the new fuel pump on the assembly and everything tightened down, lower the fuel pump assembly back into the tank. Use a new O-ring seal on the tank.

5

Reinstallation is the reverse of removal. Reinstall the locking ring over the pump, and turn it clockwise to lock the pump in place. Roll the tank back under the car on the jack, and slowly lift it in place. Have your assistant steady the tank while you reattach the fuel lines and wiring harness plugs. Lift the tank into place, and reinstall the straps -- torque the straps to 25 foot-pounds. Connect the negative battery cable. Turn the ignition key to the "on" position, and give the pump five to ten seconds to prime; you should hear the change in pitch when the pump primes. Go back under the car, and check for leaks in the fuel line connections.