Guest borat Posted August 23, 2006 Share Posted August 23, 2006 Hello everyone. Last week I picked up a '93 Jap-spec TT auto. The car is fantastic apart from one thing; the brakes. To be more precise, the rear offside wheel is locking up under virtually no brake pressure. It's actually becoming quite dangerous . The previous owner told me that the ABS and traction control had both been deactivated. I've since inspected all the brakes briefly, and can see no obvious reason for the lockups. The fluid has been completely flushed with Motul RBF, and I've even fitted new braided hoses. If anything, these 2 things have made the problem worse. I've also tried re-enabling the ABS, which seems to be be activating (you can feel it through the pedal, and there's no ABS fault light), but strangely doesn't stop the lockup ??? There are no ECU error codes stored, either. I've now hit a brick wall. Any help on this at all would be appreciated, as at the minute I can't really enjoy the car. Cheers, Owen Link to comment Share on other sites More sharing options...
Rob Dublin Posted August 23, 2006 Share Posted August 23, 2006 Caliper/drum problem? Is there a brake bias favoring the affected wheel too much? Link to comment Share on other sites More sharing options...
Kranz Posted August 23, 2006 Share Posted August 23, 2006 the rear offside wheel is locking up under virtually no brake pressure. Owen, This doesn't sound too good. If one brake is locking up and the rest aren't then the one locking up must be doing the majority of the braking. If its doing the majority of the braking it must be getting the majority of the brake pressure. 1) Did all the brakes bleed ok? 2) Did you "exercise" the calipers on each corner to check that they are free? You say that bleeding & fitting the aeroquip hoses made it worse.... That would suggest air in the system that is preventing all the brakes operating. I'm guessing that the supe is a split front/rear twin line braking system that has a pressure regulator for the rear? If one rear caliper (the one not locking up) is siezed or has air in the system and the rear pressure regulator is faulty then this may lock up the one rear wheel. Try un-siezing the calipers if you have't already done so. Failing that Toyota can do a pressure check front to rear for you to determine if you're getting too much pressure to the rear. Link to comment Share on other sites More sharing options...
Guest borat Posted August 25, 2006 Share Posted August 25, 2006 Thanks for the replies, guys. Unfortunately, I've checked all the things you pointed out. The bleeding went without hitch, and all the calipers were very free-moving on the slide pins. I'm thinking something's wrong with the proportioning valve, but it looks like that's integrated into the ABS unit on this car (am I right?). I suppose I was hoping it was a common Supra fault with an easy fix, but it looks like I'm out of luck. If anyone else has any ideas, I'm open to suggestions.... Link to comment Share on other sites More sharing options...
Bob Posted August 25, 2006 Share Posted August 25, 2006 I'd give Chris Wilson a bell and see if he's encountered something like this before. He knows the odd bits and bobs about brakes, does Chris Link to comment Share on other sites More sharing options...
Paul_SWZ Posted August 25, 2006 Share Posted August 25, 2006 If you push the pedal a few times with the engine turned off does the pedal go rock hard or feel squidgy at the top ? Link to comment Share on other sites More sharing options...
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