4 Symptoms of a Bad Brake Booster and Replacement Cost


When you step on the brake pedal, you normally don’t have to put a lot of pressure on it for the vehicle to slow down. The reason for this can be attributed to a component of the braking system called the brake booster. The function of the brake booster is to amplify the pressure as you press down on the brake pedal. That way, you don’t have to press down too hard on the brake pedal to slow the vehicle down. This creates a much safer driving experience.

The Top 4 Symptoms of a Bad Brake Booster

Of course, there could be situations where the brake booster will go bad. The symptoms may not seem extremely serious in the beginning, but you shouldn’t drive your vehicle anyway. Take your vehicle to your local auto body shop or else you may soon not be able to brake at all. Then you’ll really be in trouble.

Below are the top 4 symptoms to watch out for.

  1. Stiff Pedal – Since a good brake booster will make it easier to push down on the brake pedal, a bad brake booster will make it more difficult. You should notice the brake pedal feeling very stiff and hard as you try to press down on it. This will be the most obvious symptom of a bad brake booster, so you should get it replaced right away.
  2. High Brake Pedal – Along with the stiff brake pedal, you will notice that it is a lot higher than it should be. This forces you to lift your foot higher just to reach the brake pedal, which is a dangerous situation to be in while driving. If you forget about this and must brake suddenly, you could have problems. So, take your car to the shop whenever you notice a high brake pedal like this.
  3. Takes Longer to Stop – Even when you press down hard on the brake pedal, it may still take longer than normal for it to stop. With a bad brake booster, the pedal isn’t getting the power it needs to make it work quickly. This will make the time it takes to stop last longer. Obviously, this is extremely dangerous while driving because you might need to brake quickly to prevent a crash or save your life. If there are rough weather conditions outside, then it can be even more dangerous. Therefore, get the brake booster replaced immediately before it’s too late.
  4. Engine Stalls – The brake booster has a diaphragm in it which prevents air from getting through the seal. If the diaphragm becomes faulty and air gets through the seal, then your engine will appear like it’s stalling each time you press down on the brake pedal. This could lead to worse problems than just bad brakes. You could start having engine problems too from this. That will open all new kinds of problems that you don’t want to have.

Replacement Cost

There is an easy way to test the brake boosters at your house. While the vehicle is off, press down and up on the brake pedal about 6 times. This will get rid of any vacuum that is stored in there. Now turn on your vehicle while lightly applying pressure to the brake pedal. If the pedal slightly falls from your foot and is then firm, then your booster is fine. If the pedal is stiff and has trouble dropping, then the booster is likely bad.

Read also: 5 causes of manual transmission shifting hard especially from 1st to 2nd

The average cost to replace a bad brake booster is between $290 and $720. For the parts, you can expect to pay anywhere from $160 to $550. For the labor, you can expect to pay anywhere from $130 to $170. There will be other fees and taxes included in these prices as well. The costs really depend on the make and model of your vehicle and the labor rates of your auto body shop. It is always a good idea to shop around before choosing a shop to work on your vehicle.



  1. Bree Ward 20 February, 2019 at 11:55 Reply

    I agree with you when you said that stiff pedal is a sign of a malfunctioning brake as it might be an indicator of a bad brake booster. I heard my husband complaining about the brake of our car being hard to step on. He needs to have it checked in case it’s no longer working properly. This can cause serious accidents if the brakes stay unchecked. Thanks for the helpful reminder.

    • Ron 27 July, 2019 at 03:35 Reply

      Julian, No , if you have a soft pedal, that means leak in the brk system or air . Bad booster will be a hard pedal or engine light on for lean conditions meaning the booster has a vacuum leak

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