How to Change a Fuel Pump on Cadillac Cars

by Contributing WriterUpdated June 12, 2017

In any Cadillac car you will have to take off the fuel tank to change the fuel pump. Taking off the fuel tank is a much easier job if it is empty, but this is usually not the case when the fuel pump goes out. You can siphon the fuel out with a hose before you take the fuel tank down; this will save you a lot of trouble when lowering the tank and moving away from the vehicle.

Under The Hood:

 How to Change a Fuel Pump on a 1994 Cadillac DeVille

Park the DeVille on a level surface and put the wheel chocks around the front wheels. Lift the rear of the Cadillac with the jack and put jack stands under the rear axle.

Place the jack under the gas tank. Unbolt the gas tank straps from the chassis with the 3/8-inch ratchet, extension and sockets. Lower the jack down until you can access the top of the tank. Crawl under the Cadillac and locate the gas tank, which is near the rear axle. Remove the hose clamps holding the fuel lines to the tank and the fuel filler neck to the tank using the flathead screwdriver. Unplug the wiring to the fuel pump with your hands. Then lower the tank the rest of the way and pull the tank out from under the Cadillac.

Turn the locking ring on the top of the fuel tank sending unit and fuel pump assembly using the brass drift and brass hammer. Lift the sending unit/fuel pump assembly straight up out of the tank. Locate the fuel pump, which is bottom of the tank. Pull the pump straight up out of the assembly and move it to the side.

Pull off the strainer from the fuel pump with your hands and install it on the replacement fuel pump. Install the replacement fuel pump onto the assembly with your hands. Install the replacement fuel pump into the tank and use the brass drift and brass hammer to install the locking ring and secure the assembly into the tank.

Lift the tank up into the chassis and reconnect the fuel lines and electrical connections to the tank using the flathead screwdriver. Bolt the tank mounting straps onto the chassis with the 3/8-inch ratchet, extension and sockets. Lower the Cadillac off of the jack stands using the jack.

Items you will need

  • Wheel chocks

  • Jack

  • Jack stands

  • 3/8-inch ratchet, extension and socket set

  • Brass hammer

  • Brass drift

  • Flathead screwdriver

  • Replacement fuel pump

 How to Change the Fuel Pump in an El Dorado

Open the hood. Remove the negative battery terminal nut. Pull off the negative cable from the battery.

Open the gas cap. Insert the siphon into the gas filler hose. Lower the siphon until it reaches below the gas line in the tank. Pump the gas out of the tank into spare gas cans. This step makes it much easier and safer to remove the fuel tank.

Engage the emergency parking brake. Raise the rear of the Eldorado with a car jack. Set two jack stands underneath the Eldorado to stabilize it while you work below the car.

Put on your latex gloves. Loosen the securing rings that hold the ventilation hose and filler hose to the fuel tank with your screwdriver. Pull off the rings. Pull the hoses off of the fuel tank joints.

Set the floor jack below the fuel tank. Remove the front strap holding the fuel tank in place with a socket wrench. Pry the fuel tank away from the frame rail with a screwdriver to set the loosened end of it on the floor jack.

Locate the fuel pump above the revealed top of the fuel tank. Remove the return fuel hose, emissions evaporation hose and wiring connectors from the pump. Disconnect the electrical connectors by pressing in on the side tabs. Slip the quick-disconnect tool around the fitting on one of the hoses. Press the quick-disconnect tool together. Pull off the hose. Repeat this process for the other hose.

Remove the other strap holding the tank in place. Push the floor jack out from underneath the Eldorado with the tank on top of it.

Clean the top of the tank with the acetone-based cleaning agent and some rags. Dislodge the locking ring tabs around the fuel pump from the slots in the fuel tank by hitting them with a brass punch and mallet until they are loose enough to pull out. Lift off the ring. Pull up on the fuel pump slightly, enough to reach into the opening. Press away on the tabs on the fuel tank to release the pump from the tank. Navigate the fuel pump out of the opening on the tank. Remove the fuel pump gasket.

Smear the new gasket from the fuel pump kit with fresh motor oil. Place it over the opening to the tank. Insert the new fuel pump into the tank. Seat it all the way to the bottom of the tank. Listen for the tabs on the tank to catch on the slots of the fuel pump, securing it in place. Secure the locking ring around the fuel pump.

Reinstall the fuel tank below the Eldorado. Connect all of the hoses and electrical connectors you removed earlier.

Refill the fuel pump with the fuel you siphoned out. Reconnect the engine bay battery. Turn on the Eldorado. Turn off the Eldorado after three seconds. Turn the Eldorado on and off like this five or six more times until the engine cranks. This indicates that fuel has been pumped through the system. Check that there are no fuel leaks below the Eldorado. Turn off the car if there is a leak. Refit any leaking joints. Turn the Cadillac back on and check again. Lower the vehicle to the ground if there are no leaks.

Items you will need

  • Siphon and pump

  • Gas cans

  • Car jack

  • Two jack stands

  • Floor jack

  • Latex gloves

  • Flat head screwdriver

  • Hose quick-disconnect tool

  • Hammer

  • Chisel

  • Socket wrench set

  • Acetone-based cleaning agent and rag

  • Replacement fuel pump

 How to Replace the Fuel Pump on 1993 Cadillac

Remove the negative battery cable. Jack the rear of the car up with the floor and place jack stands under the chassis on either side of the vehicle. Let the car down on the jack stands. Slide under the car and go directly behind the fuel tank. Find and disconnect the electrical connector to the fuel pump.

Start the vehicle and let it run until it stops on its own, this should be only a few seconds if it starts at all. Starting the car in this manner, with the fuel pump not working, will use up all the fuel in the line and relieve any pressure.

Loosen the hose clamp that holds the fuel filler hose to the fuel tank. Roll the jack stand under the car and directly under the fuel tank. Raise the jack until it is touching the bottom of the tank. Use the socket set and ratchet to remove the two metal straps that hold the tank in place. Lower the tank just enough to get your hand to the top.

Reach on top of the tank and unhook the fuel intake line, the return line and the vent-to-canister lines. Lower the fuel tank down to the ground and pull it from under the car.

Place the flat head screwdriver on the tab that is attached to the locking ring on the round hatch on the fuel tank. Tap the screwdriver so that the locking ring will turn counterclockwise. Remove the locking ring and the hatch cover.

Pull the old fuel pump out of its cradle that is attached to the bottom of the hatch cover. Replace it with the new fuel pump and replace the hatch cover. Place the locking ring over the cover and gently tap it clockwise until it is seated securely.

Jack the tank back into position under the car. Leave enough room to be able to put the 3 fuel lines back on. Replace the fuel lines and jack the fuel tank all the way up into place. Reattach the two metal straps that hold the tank in place. Tighten the bolts until the straps are secure. Reconnect the electrical connector and gently pull on it to make sure it is connected properly.

Put the floor jack on a strong part of the chassis and jack the car up and off of the jack stands. Remove the jack stands and lower the car onto the ground. Replace the battery cable and start the vehicle. Let the vehicle run fro a couple of minutes to make sure the pump is working correctly.

Items you will need

  • Floor jack

  • Jack stands

  • Socket set

  • Ratchet

  • Flat head screwdriver

  • Hammer

 How to Replace the Fuel Pump on a Cadillac

Attach the bleeder hose fitting to the fuel pressure connector inside the compartment engine and alleviate the fuel pressure.

Detach the negative battery cable.

Raise the vehicle on a lift or with secure jack stands.

Detach the electrical plug located at the rear of the tank.

Disengage both fuel lines.

Slide the floor jack beneath the fuel tank.

Raise the floor jack until it is touching the tank.

Unscrew the bolts from the rear exhaust heat shield.

Unfasten the tank straps from the tank.

Lower the tank with the floor jack. This should be done slowly.

Detach the locking ring from the pump assembly.

Lift the pump assembly out of the fuel tank.

Install the new fuel pump assembly into the tank.

Attach the locking ring to the pump assembly.

Raise the tank with the floor jack. Again, this should be done slowly.

Fasten the tank straps to the tank.

Screw the removed bolts to the rear exhaust heat shield.

Engage the fuel lines.

Attach the electrical plug at the rear of the tank.

Connect the negative battery cable.

Items you will need

  • Bleeder hose fitting

  • Floor jack

  • Set of mechanic wrenches

  • New fuel pump assembly

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