A Step-By-Step Guide to Replacing Your Car's Mechanical Fuel Pump

Female motor mechanic working on a car engine.
Mechanic working on a car engine. Portra / Getty Images

Your vehicle's mechanical fuel pump is a fairly reliable piece of low-tech equipment. But like any of your car's components, mechanical parts can wear down or break. Fortunately, replacing a broken fuel pump is a fairly simple task that you can accomplish at home in about an hour or two.

What You Will Need

Replacing your fuel pump is a messy job, so be sure you're dressed appropriately. You will also need some common tools, as well.

  • Ratchet wrench set with universal joint
  • Tubing or open-end wrenches
  • Hose clamp pliers or screwdriver
  • Bolt or wooden dowel
  • Shop rags
  • Gasket sealer
  • Fire extinguisher rated for gasoline fires

Remember, you will be working around fuel and fuel vapors, so be sure that your workspace is well ventilated. Do not smoke, use an open flame, or do anything that may cause sparks or otherwise present a safety hazard.

Replacing Your Fuel Pump

Once you've gathered your tools, turned off your vehicle, and made sure you're working in a safe area, you can begin working. First, you'll need to remove the old fuel pump in this order:

  1. Disconnect the negative battery cable.

  2. Disconnect the fuel tank hose at the fuel pump and plug the hose with a bolt or wooden dowel to keep any fuel from flowing out. Also, disconnect the vapor-return hose if the vehicle is equipped with one. Be sure to wipe up any gas that spills.

  3. Carefully examine the old fuel hose; if it is frayed or cracked, replace it with new fuel line hose.

  1. Disconnect the outlet line to the carburetor. Use a wrench on the fuel pump fitting and another on the line nut.

  2. Remove the two attaching bolts and extract the old fuel pump. Clean off any old gasket material from the mounting surface of the engine using a shop rag.

Once the old fuel pump has been removed, it's time to prep and install the new unit in this order:

  1. Apply a coat of gasket sealer on both sides of the new gasket. Put the attaching bolts through the new pump and slip the gasket over the bolts.

  2. Install the new pump on the engine. Make sure that push rod is correctly installed in both the engine and the fuel pump. If the push rod slides out, you can pack it with some heavy grease to hold it in place while you install the pump.

  3. Attach the fuel outlet line that runs to the carburetor. If it's difficult to connect, remove the other end of the line from the carburetor. Connect the line to the fuel pump, and then reattach the other end to the carburetor. Use a wrench to hold the fuel pump fitting and tighten the line nut with another wrench.

  4. Attach the fuel inlet hose from the gas tank and the vapor-return hose. Tighten all clamps.

  5. Reconnect the battery ground cable, start the vehicle, and check for leaks.

Once you've inspected your work and made sure it's free of leaks, your vehicle is good to go.