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How to Change a Brake Booster

by Dan Ferrell

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.

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.

Items you will need

About the Author

Since 2003 Dan Ferrell has contributed general and consumer-oriented news to television and the Web. His work has appeared in Texas, New Mexico and Miami and on various websites. Ferrell is a certified automation and control technician from the Advanced Technology Center in El Paso, Texas.

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