Skip the auto shop - Our mechanics make house calls

Q: Could the brake servo booster that the master cylinder attaches to cause the brake pedal's excessive travel?

asked by on

I have a Toyota avensis 2008 model. My issue is the brake pedal is traveling to the floor when brakes are applied. I have inspected the brake lines, calipers and have changed the master cylinder. But the problem has not gone. The only other option am remaining with is the brake servo booster that the master cylinder is attached to. When I step on the brake pedal a sound like of some pressure being released comes. Could this servo booster be the issue?

My car has 150000 miles.
My car has an automatic transmission.

A: Hi there. Typically, when a brake booster f...

Hi there. Typically, when a brake booster fails, the result is a hard to push brake pedal. The pressure release you hear is engine vacuum and may be normal considering, the brake pedal travels to the floor. With no apparent leak(s) in the hydraulic braking system, the master cylinder internally bypassing is the most common failure. Having replaced the master cylinder, this leads me to believe, there may be air trapped and a flush may resolve this concern. Assuming, the vehicle is equipped with ABS (anti-lock brake system). The ABS hydraulic modulator assembly may be internally bypassing. I recommend having your vehicle’s brake pedal issue diagnosed and repaired by a certified technician, such as one from YourMechanic.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Is it legal to have a clear yellow sticker over a headlight or fog light?

Headlight covers are legal, as long as the amount of light that gets through meets state requirements. Each state has its own requirements, so you will need to contact your state police or highway patrol to know for sure. Local...

Q: Rear shock knocking on a 2008 Saab

You've changed them all, but did you change the mounts on them, too? Because a lot of times, the mounts go bad. Make sure that they are torqued on nice and tight. Because all of the body of your car...

Q: Brake pedal stuck to floor - 1972 Volkswagen Super Beetle

Hello. There is a return spring on the assembly that must be dislodged or broken somehow, and when this happens there will be issues with the pedal returning. Have the pedal assembly and the hydraulic portion of the system inspected...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.