How to Replace a Power Brake Booster

The brake booster provides power assistance during braking. Inside there is a disc-like diaphragm that separates the booster’s two halves. When the engine is running, vacuum is applied to both sides of the booster. When the driver steps on the brakes, the pedal operates a valve which allows outside air to enter. This allows atmospheric pressure to enter the booster, creating a pressure differential that forces the booster power forward into the master cylinder for power assist. When the brakes are released, vacuum returns to both sides of the booster and a spring returns the diaphragm to its original position.

If the power brake booster is not functioning properly, you will notice problems such as the brake pedal being very hard to press, and the vehicle taking longer than normal to come to a stop. It may be time to replace the power brake booster.

Materials Needed

  • Pliers
  • Protective gloves
  • Ratchet, sockets and extension
  • Repair manuals (optional)
  • Replacement brake booster
  • Safety glasses
  • Screwdriver and/or small pick

Part 1 of 2: Remove the faulty brake booster

How to Replace a Power Brake Booster 2

Step 1: Locate the brake booster. The brake booster will be mounted to the firewall on the driver’s side.

How to Replace a Power Brake Booster 3

Step 2: Remove the master cylinder from the brake booster. Remove the master cylinder fasteners using a ratchet or wrench. Then pull the master cylinder away from the booster. Typically, the brake lines are long enough that this can be done without disconnecting the lines.

How to Replace a Power Brake Booster 4

Step 3: Disconnect the booster vacuum supply line. Remove the hose clamp by squeezing it with a pair of pliers and sliding it away from the booster. Then gently remove the hose by pulling it away from the booster.

How to Replace a Power Brake Booster 5

Step 4: Disconnect the booster pushrod from the brake pedal. Using a small screwdriver or pick, remove the retaining clip from the booster pushrod. Then remove the pushrod from the brake pedal.

How to Replace a Power Brake Booster 6

Step 5: Remove the brake booster fasteners. Remove the fasteners securing the booster to the bulkhead. These are typically located under the dashboard. The best way to reach them is by using a ratchet with an extension.

How to Replace a Power Brake Booster 7

Step 6: Remove the brake booster. Pull the booster away from the firewall and remove it from the vehicle.

Part 2 of 2: Install the new brake booster

How to Replace a Power Brake Booster 8

Step 1: Position the new brake booster unit. Place the new brake booster in the same location that the old one was removed from.

How to Replace a Power Brake Booster 9

Step 2: Reinstall the fasteners. Reinstall the brake booster fasteners and tighten them down using a ratchet and extension.

How to Replace a Power Brake Booster 10

Step 3: Reconnect the pushrod to the brake pedal. Reinstall the pushrod onto the brake pedal and put the clip back on.

How to Replace a Power Brake Booster 11

Step 4: Reconnect the booster vacuum hose. Slide the vacuum hose back onto the booster. Then reinstall the hose clamp by squeezing it with a pair of pliers and sliding it onto the booster.

How to Replace a Power Brake Booster 12

Step 5: Reinstall the master cylinder. Reinstall the master cylinder and tighten down the mounting bolts using a ratchet or wrench.

Replacing a brake booster can be tough. If this seems like something you’d rather leave to the professionals, YourMechanic offers expert brake booster replacement conveniently done at the time and place of your choice.


The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Replace a Lost or Stolen Car Title in New York
Do Do you have plans of selling your car in the future? What about transferring ownership, perhaps passing it over to one of your kids when they turn 16? In order to do either of these you’ll need to have...
What Is Brake Dust?
It's It's time to wash the car, but when you get to the wheels they are covered by a hard to remove gray dust. Even after you clean it off, it comes back quickly. Welcome to the world of brake...
How to Replace a Power Seat Switch
The power seat switch in your car lets you adjust your seat to your preferences. If broken, especially for the driver seat, it should be replaced.

Related questions

I have code c1223 in the car i have problem in the brake and the ABS light or VSC is not alarming in the dash.

Hi there. Unfortunately when you get this code on this vehicle it is due to an internal malfunction of the ABS unit. In some cases it can be a bad connection or a power supply problem so those should be...

Abs module is no good. I have another one from junk yard with the same year and FWD and engine. Will it work?

Hi there. As long as the ABS module is the same design and has the same ports on it then it will work just fine on your vehicle. Be sure to bleed all of the brake lines after replacing the...

Rusted brake line

If you have one brake line rusted out, then I would suggest having all the brake lines checked for rust damage. If one line has a leak then the rest are most likely rusted to the point of failure also....

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com