2003 Discovery II

Came home from a short trip for a very short stop at home. Everything was fine on that trip.

Started back up to head out and all four brakes locked up such that it was like I was pulling a 10000 pound load. No warning lights, no OBD codes, just dragging/smoking brakes. The pedal is very hard, like its already being stomped on and won't move very much more.

Any ideas on where to look first? I would suspect maybe the master cylinder? Doesn't seem the ABS would fail this way, I would think it would fail so that there was no ABS, not that the brakes locked up.

Any help is appreciated. Thanks in advance.

 

UPDATE

Well, I went out this evening (cool here in South Carolina at about 45 degrees) to check the brakes. They work fine, pedal pressure is normal, braking is normal, and there doesn't appear to be any dragging or locking up? I had put in fluid not too long before the first drive I mentioned before. I wonder if I put in too much and after some spirited braking (don't think I did more than normal but maybe I did) it heated up and there was no place for it to go so when I put on the brakes it stayed in the position?

Just a data point. If not then its a problem I'll have to keep checking on. I don't want to get to far away from home though until I have restored confidence in the fact that they won't lock up.

Smokey

 

Sounds like a traction control issue. I'm guessing it's a bad abs sensor, but the only way to know is with an abs amigo.

BTW, if the problem comes back, pull the abs fuse to keep the truck drivable. You may want to preemptively pull it so the brakes dont lock up at 65mph. All it affects is the TC/ABS system, so probly you'll be ok for a little while.

 

Went out today and the brakes weren't locked. I drove awhile and it seemed okay. I had to come to a few stops and it felt pretty good but each time it seemed like it started to drag on all for wheels a little more each time. Finally, it was nearly completely locked up and I had to really gun it to even get it to move. I went to a safe place to pull over and walked home. I will go out tomorrow morning and see if they are still locked. Still no codes at all showing.

I'll pull the ABS fuse like Dr suggested but I'm thinking it may be in the master cylinder since it effects all 4 wheels and it gets worse slowly the more you use the brakes. I'm supposing that something is leaking by internal to the master cylinder putting a hydraulic lock on the piston keeping it in the "brake positon". Once it sets for awhile it may leak back by and be okay until you push on the brakes and it starts to get the hydraulic lock. Just a thought, not yet tested. Once I get it home, I figure I can set with the engine running and push hard on the brakes a few times. If it locks the brakes up it would seem to confirm my suspicion.

 

Hello ,, did you confirm what the fault was , ie was it the Mater Brake Cylinder ,, if yes - how big a job to replace ? I have a similar issue

 

The original poster last posted 3 years ago.

 

but... replacing the master cylinder is not a big job at all. the hardest parts will be loosening the fluid lines (they tend to be pretty tight) and then bleeding each wheel.

 

To me...it sounds like the original poster overfilled his brake reservoir, and when the fluid got hot and expanded...it had no where to go...causing the brake to not release. There is a max line on the reservoir for a reason.

Brian.