rear brakes locking up on 2001 tdi

[moreforyou]

i've read a post with someone with the same problem, but the solution wasn't clear. i'd like to do anything to avoid going to the dealer, as it's something i really cannot afford.

so basically, the problem is: when i start up the car, the brakes feel rather spongy. as i drive along the brake pedal gets stiffer and stiffer to the point where if i barely press it, it's like slamming on the brakes. if i stop the car and press hard on the pedal, i can bleed the extra pressure off and keep driving. i have to do this every 5 minutes or so, or the brakes will totally lock up.

the first time this happened, i didn't really know what was going on, so i had to basically floor it to keep the car moving. when i stopped the rear brakes were very hot and stunk horribly.

if anyone can shine some light on this problem it would be MUCH appreciated. thank you.

 

[Rob Mayercik]

Heard something like this on Car Talk once - different type of car, but they thought that there might be something funky happening with the power brake booster.

HTH,

Rob

 

[GoFaster]

The master cylinder piston isn't retracting far enough to uncover the vent holes inside. That means either something's wrong internally with the master cylinder itself, or something outside the master cylinder (most likely the vacuum servo for the power brakes) isn't letting the piston go all the way back.

 

[spifflifkin]

Check out this post. Brakes hung-up?
Good luck!

 

[Cheshire Cat]

Brian's right, it's the master cylinder for whatever reason, as the brakes rub and get hotter the fluid expands and/or the moisture boils and applies more pressure hence more braking effect, had similar with a '53 Morris Cowley some years back, hope this helps. Nic