How to Change a Brake Booster

The vacuum type brake booster on your vehicle multiplies the force you apply to the brake pedal to slow or stop the car. Engine vacuum acts on a diaphragm inside the booster, pushing a rod into the master cylinder to create the necessary pressure in the brake system. This booster diaphragm may develop punctures and other related mechanical failures after years of service. A failing booster may hinder your ability to brake making necessary to change the unit.

Things You'll Need

  • Nose pliers
  • Ratchet and socket
  • Ratchet extension
  • Slip joint pliers
  • Wrench
  • New cotter pin

Removing the Old Brake Booster

  • Park your car in a safe place with enough room to work around the front and driver side of the vehicle.

  • Locate the booster push rod connected to the brake pedal.

  • Remove the cotter pin securing the booster push rod pin to the brake pedal using a pair of nose pliers.

  • Release the push rod pin from the brake pedal and slide the push rod off the brake pedal.

  • Unscrew the four mounting nuts off the brake booster studs using a ratchet, ratchet extension and socket. You should be able to see the four booster studs extending through the firewall, in front of the brake pedal.

  • Disconnect the vacuum hose from the brake booster, working from the engine compartment. Use a pair of slip joint pliers.

  • Remove the two nuts holding the brake master cylinder to the brake booster. Use a wrench or ratchet and socket.

  • Separate the brake master cylinder from the booster just enough to make room for booster removal.

  • Pull the brake booster off the firewall and remove it from the vehicle.

Installing the New Brake Booster

  • Set the new booster in place by sliding the push rod and four mounting studs through the mounting holes on the firewall.

  • Slide the brake master cylinder flange over the two mounting studs on the brake booster.

  • Start the two brake master cylinder mounting nuts by hand to avoid damage to the threads.

  • Tighten the two brake master cylinder mounting nuts using a wrench or ratchet and socket.

  • Connect the vacuum hose to the brake booster.

  • Screw the four mounting nuts to the brake booster working from inside the vehicle. Start the nuts by hand to avoid damaging the threads.

  • Tighten the four mounting nuts using the ratchet, ratchet extension and socket.

  • Position the brake booster push rod over the brake pedal and slide the push rod pin.

  • Install a new cotter pin to secure the booster push rod to the brake pedal.