HELP HELP HELP BRAKES
 

1995 90 2wh drive, right ft & lt rear brakes locking up. ABS light not on. after 1 hr or so they will free up- but drive it again & soon after thay lock again.
any help ? even with ABS (fuse) pulled they still lock
bentley cd/ book no help
no dash warning blubs lit
please any help needed !

Since Audi master cylinders...
 

are dual diagonal, that would tie the diagonally opposite corners together. Thus, I would say bad master cylinder. I had this kind of issue on my 85 5000, and likewise it happened when car got warm. I was able to confirm it was the master cylinder by (gently) tapping on it with a hammer when it was locking up. That freed up the internal pistons and unlocked the brakes.

Net, you may need a new master cylinder and then brakes, ABS, etc. bled.

yep, that is what i've gussed as well - bad master, ft seal leaking on ABS - another fourm member hooked me up with a bone yd, - i'm sure all will have to be replaced (over time0 but i'll pwr flush the entire sys a few times & hope it free's up.
another ? does the oil dipstick have a o ring for a seal ?