Hello all, I'm new to the audi game(1week).Here is my problem,when the car is cold no prob with the brakes,drive around for a while the brakes are holding all by themselves.I stop and look,the rotors are glowing red.I changed one of the front calipers, brakes and bled the front.Still have the same prob.I figured mastercylinder,just want to know what you guys thought,just want to have an idea B4 I took it to the shop.Oh,the brake and abs light comes on the goes of after a few minutes

 

My guess would be a sticky caliper. Did you have this problem, then replaced the caliper and you still have the same problem?

Unless you are stopping hard a lot, and I mean a lot, they should not be getting red hot. The only thing that I can think of that causes a rotor to get red hot is a sticking caliper. I don't see how the master cylinder could have any influence on this particular problem. That is of course I understand correctly what is going on.

Jeff

 

are both red hot, or just one? if its just one, ride down the road and let go of the steering wheel. if your car pulls to one side, its most likely a sticky caliper

A couple things about what you said
1. You should normally never change just one caliper, you should always change them in pairs. Its a rule of thumb. You dont want the pressure to be different on both brakes.
2. Try changing the hoses, thats the only other thing I can think of

My jeep had "sticking" caliper problems, and these are the steps I have had to resort to so far. Im getting an Audi very soon

 

Thanx for the reply.The problem is when I release the brake the pressure is still in the brake lines.So the brakes are still holding as I drive.Bled both front brakes and still.
.Puzzling

 

I agree..Change both calipers at the same time. Your master cylinder is not equalizing pressure or releasing pressure once you have released the foot brake. It could be due to bad seals in the cylinder or clogged brake lines. I would pressure test and bleed the entire system and see if the problem persists. You will destroy your rotors and pads if you continue to drive this way. There is a good chance you have already warped your rotors due to the heat so the new pads will just wear unevenly and you'll blow through another set of brakes before you know it. I believe that Les Scwab still pressure tests brake systems. They will be able to tell you right away. Stay away from the dealer unless you have no other choice. Good luck!

 

Thanx agian,sounds about right.I'll get the system flushed and see if it makes a difference

 

prbayha, that makes perfect sense.

 

Brakes holding when warm is often due to moisture in the hydraulic fluid. When cold, everything performs fine... when warm, the moisture heats up and expands where the hydraulic fluid would not... results in brakes not releasing entirely. See this often in off-road vehicles that have been dunked in a river or creek or older vehicles parked for years. May or may not be relative to your issue, but thought I would throw it out there given your 'cold' braking seems to be fine. While replacing both calipers at once is certainly recommended, the issues associated with disimilar aged calipers is not normally as extreme as your problem. Have replaced single caliper only for budget concious customers many times with no problems (not on Audis though).

JJJ