Brake pedal goes to the floor

For the past several weeks, my daughter reports that she has to put her foot almost all the way to the floor to get the brakes to work. The brakes do not have an effect until her foot is 1-2 inches from the floor. It usually happens after she has been driving for a while without pressing the brakes. I’ve driven the car numerous times but haven’t been able to replicate the problem. Her commute is approximately 10 miles each way in stop and go traffic. The car is a Volvo xc70 with 200k+ miles. I’ve had it looked at by a mechanic who didn’t find anything but it’s continuing to happen. I’m suspicious that it may be a master cylinder problem and concerned about complete brake failure – should I be?

Yes, you should be concerned. Have it checked soon. It could be air in the system, the power brake booster, the master cylinder or the ABS. It could be something else. Take it to a trusted independent mechanic and tell him everything your daughter said and what you experienced. Take her along, if possible. It is the details that will help diagnose the problem.

Put very gentle pressure on the brake pedal and see if it falls away…If so, replace the master cylinder…

Brake failure (along with injuries to innocent parties) is certainly possible here. This car shouldn’t be on the road, in my opinion.

This car is unsafe to drive. I urge you, please have it towed to a qualified independent shop for diagnosis and repair. NOT the guy that “couldn’t find anything”.

I’m with Caddyman on this one but regardless of the cause I’m also with the same mountainbike .

When this happens again, have your daughter check each wheel to see if one is exceptionaly hot. Just touch the wheel rim and see if one is hotter. It is a possibility that a caliper is sticking and boiling the fluid disabling one of the dual systems. When the caliper has a chance to cool, the fluid will be drawn back in and the system operates okey.

Just an idea that would explain the intermittancy of the occurance.

Has the brake fluid EVER been changed? The reason I ask is because you’re complaint sounds like the brake fluid is boiling in the lines when it is acting up, but reverting to liquid soon after and behaving normally again. Badly contaminated fluid can compromise the fluid’s ability to resist heat and compression. It Iis the most neglected fluid, and with 200,000 miles on the car, could be at a critical state.