Brakes keep failing on journeys over bout 30 miles

JOEEREIDD

MEMBER
2001 VAUXHALL VECTRA
85,000 MILES

Brakes keep failing on journeys over bout 30 miles. Er for while brakes work again. Doesn't happen on short journeys. Have had the brake master cylinder changed and checked for leaks. Brake pedal usually bites half way. When it happens pedal pushes to floor and just about slows the car. It's as if pressure being lost. Have to keep pumping brake pedal then it ok again.

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

It sounds like your brakes might be overheating and you are experiencing brake fade.
You could have overheated brake components due to sticking caliper(s). When a caliper sticks, it keeps the brake pads in a constant contact with the rotor as the vehicle drives. This friction overheats the brake caliper, rotor, and the fluid. Overheated brake components will perform poorly when the pedal gets depressed. When you pump the pedal, it helps to build the pressure back up for the brakes to function properly.

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

Keep in mind that many times the caliper will stick due to having collapsed brake hose to the caliper. Those rubber hoses can deteriorate on the inside and collapse, this will prevent brake fluid to go back when the brake pedal gets released. Which leads to the pads sticking to the rotor(s), causing to overheat.

After the long drive, check to see if the brake system appears to be overheated. Most of the time you can feel excessive heat coming off of the brakes as you get close to it.

When a brake does overheat it is ideal to replace the pads, rotors, caliper as well as the hose. As overheated components tends to fail in short period of time.

https://www.2carpros.com/articles/brake-caliper-replacement

Please let me know of any questions.
Thank you.

Image (Click to make bigger)