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.

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?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Could the brake servo booster that the master cylinder attaches to cause the brake pedal's excessive travel?

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: What do I do if the moon roof tilt won’t close?

There is a possibility that when you try and close the moon roof tilt, it will close and then partially reopen. If so, simply stop the vehicle and perform the relearning process for the moon roof. Press and...

Q: Noise while idling, difficulty shifting

Without hearing the noise myself, it will be hard to make an accurate assessment for your 2008 Chrysler Aspen. In many cases, where the noise source is not obvious, chassis ears may need to be used to locate the source...

Q: Possible booster needed - 1996 Lexus LX450

A "normal" brake job only addresses wearing parts like brake pads and rotors (or brake shoes and drums on drum brake vehicles). The brake booster rarely fails, and then usually because the brake master cylinder has allowed brake fluid to...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
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.