Symptoms of a Bad or Failing Hydraulic Brake Booster

Hydraulic brake boosters are a type of brake booster found on many road going cars and trucks. Though not as common as conventional vacuum operated brake boosters, they serve the same purpose, to provide assistance to the brake system in order to reduce pedal effort and make brakes easier to operate. They differ from vacuum brake boosters, in that they operate using hydraulic pressure to assist the brakes, instead of engine vacuum. The boosters operate using hydraulic pressure generated by the vehicle’s power steering pump, or a dedicated hydraulic pump. Hydraulic brake boosters work especially well for vehicles equipped with diesel engines, where there is considerably less engine vacuum generated and therefore accessible to power accessories, in comparison to gasoline engines.

When the hydraulic brake booster fails or has an issue it can cause problems operating the vehicle’s brakes, which can become a safety concern. Usually a bad or failing hydraulic brake booster will produce a few symptoms that can alert the driver of an issue.

1. Reduced braking power

One of the first symptoms of an issue with the brake booster is reduced braking power. If there is any issue with the booster, or a compromise in the pressure of the system, the vehicle may experience reduced braking power. You may notice that the vehicle takes longer to come to a stop when the brakes are applied, and that the brakes do not respond as rapidly as they used to. Similar symptoms can also be caused by other issues with the vehicle’s brake system, so a proper diagnosis is recommended if you are unsure of the issue.

2. Brake pedal hard to press

Another common symptom of an issue with the hydraulic brake booster is a hard brake pedal. If the brake booster fails the power assistance for the brakes will be disabled and the pedal will become hard to press. A hard pedal will require significantly more effort to depress, which will result in reduced braking power and increased pedal effort.

3. Fluid leaks

Another symptom of an issue with the vehicle’s hydraulic brake booster is fluid leaks. If any of the seals or hoses that are a part of the hydraulic brake booster system wear out or rupture, they may leak fluid. Depending on the severity of the leak this may produce drips or puddles of hydraulic fluid beneath the vehicle. Any leaks present in the hydraulic brake booster system should be addressed as quickly as possible, as they will eventually compromise the operation of the system, once the fluid level drops low enough.

A properly functioning hydraulic brake booster will make it easy to operate the brakes without the need for excessive force, and can cause braking, and therefore safety issues with the vehicle when it has problems. If you suspect that your vehicle may be having an issue with the hydraulic brake booster, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if the booster should be replaced.


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Jesse
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Jaguar S-Type V8-4.2L - Brake System Inspection - Palm Coast, Florida
Jesse showed up for the appointment timely and ready to work. He was polite and professional and competent. He took sufficient time to inspect the vehicle and explained in layman's terms any problems and whatever corrective work that might be required. I highly recommend Jesse and hope to have him service my vehicles again in the future if needed.
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Johnny

34 years of experience
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34 years of experience
Toyota RAV4 L4-2.4L - Brake System Inspection - Sacramento, California
Johnny arrived early which was great, he performed the inspection in less than half an hour, and gave us a complete quote for all items needing attention, including the brakes as our main concern. Johnny is fast and efficient so I scheduled the work done by him.
Ford Escape - Brake System Inspection - Sacramento, California
The convenience is worth the cost. I was also tired of the dealership not really caring about my old car. Last couple of times I had to wait well over an hour to get my car after the dealership said "It's ready!". They also wouldn't fix the things I asked saying they didn't have time and I need to come back.

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Honda Accord V6-3.0L - Brake System Inspection - Northbrook, Illinois
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16 years of experience
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Nissan Sentra L4-2.0L - Brake System Inspection - Charlotte, North Carolina
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