Expert: Mike Evans - 3/31/2010

Question
I have a 99 2.2l sunfire. After it is driven for a while the brakes start to tighten up. Enough that they start to smoke. The brake pedal becomes extremly hard to push. It is all four wheels. I have replaced the mastercylinder with a reman. and the problem is still there. If the car sits for a while the brakes start to work properly.

Answer
    I don't think I've ever heard of this happening on a relatively new car.  It is most likely the booster.  There is a valve inside the booster that applies assist when the bake pedal is pushed, and vents pressure when the pedal is released.  It is probably not releasing the pressure.  When the car sits a while the vacuum in the booster slowly leaks down.  This is not the check valve, which does the opposite.  A rebuilt booster doesn't cost much, but you might want to get a mechanic to check the system just in case I'm wrong.