Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. Symptoms of a Bad or Failing Hydraulic Brake Booster

Symptoms of a Bad or Failing Hydraulic Brake Booster

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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Still not sure about your car's issue?
Diagnose your car
What kind of issue are you experiencing?
Brakes are squeaking
Car is not starting
Car is overheating
Car is shaking (vibrating)
Fluids are leaking
Heating and A/C
Smoke or steam is coming out of the car
Warning light is on
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

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

More related articles

Symptoms of a Bad or Failing Flexible Clutch Hose
Common signs include difficulty shifting, low clutch fluid, and feeling no resistance at the clutch pedal.
P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem...
How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...

Related questions

Q: I am having a turbo sensor issue and I may have wiring issues also on my 2006 Volvo S60

Hello. If you suspect that the sensor was not replaced then that can be why the light is coming on. I would need to know what code is coming from the computer for it to be able to tell better...

Q: car shakes when put on brakes. is that rosters or pads? gonna need to get it fixed regardless

Vibration and/or shaking on application of the brakes is often due to faulty rotors (warped, or irregularly worn). If the rotors are replaced, of course the brake pads will have to be replaced as well. The recommended services to request...

Q: Brake lights don't work after replacing brake pedal switch

I can personally understand how frustrating it can be to try to get your brake lights working properly, and it looks like you have already put in a lot of effort to have it fixed! Having the information about your...