Front brakes sticking on

[barberryn]

'97 xle v6 abs
I have a weird problem that is a new one for me and my fellow mechanic buddys.
When braking normally, the front calipers grip as they should but do not release as the brake pedal is released. The rears function normally but the fronts stay "on" even for hours later. The pads on the left front are worn more than the set on the right front, if that is any hint.
The pads were only two months old and now the lefts are done at about about 1/16" left. The rights have about 1/4" left.
The calipers can be pushed back with c-clamps and are proven not to be seized. The pins are free and well lubed.
Any advice as to where to look in the hydraulic system for what would lock the front end only? I do not want to have to resort to throwing parts at the car, hoping to eventually get the problem, as that is way to expensive.

[96paseo]

Is the brake pedal very stiff and have very little travel? Before replaceing the calipers, I would suggest checking the rubber brakes lines that go to each front caliper. Remove the banjo bolt and have an assistant depress the brake pedal. Hold it over a drain pan and check for good flow of brake fluid while holding the rubber hose. If the flow of brake fluid is slow and you can feel the rubber hose expanding, it is bad. repeat same test procedure for other side. Sometimes, the rubber hose can deteriorate on the inside. This will allow brake pressure to get to the caliper but not be able to return to the master cylinder which results in a locked wheel.

[barberryn]

Finially had a nice day to get to work on the car. Pumped up pedal pressure then got out and undid the caliper brake line bolt. Very little pressure present and not much flow of fluid from caliper. Caliper still very stiff.
Darn - caliper piston stuck in bore. Funny that this occured on both sides and appeared to show up all at once but that was the case.
I reattached the line and pumped the brakes slowly to blow out the piston. Using a toothpick I picked out the inner seal ring and found rust in the groove. Also a lot of black rust/crud was built up on the outer bore edge between the main seal and the outer dirt boot. This I scraped off with a knife. Once cleaned up, the seal easily reinstalled and the piston lightly wetted with brake fluid was installed and movible by hand alone.
Bled this side then found and did the same on the other front wheel. A final brake bleed of both sides found a little more air then all clear.
Overall an easy repair and best part it was only 6 bucks for some walmart brake fluid. Just needed some courage to take the leap and pop out the pistons.
Hope this helps as I was initially stumped by the double front sieze thing.

[Mike Gerber]

Originally Posted by barberryn

Finially had a nice day to get to work on the car. Pumped up pedal pressure then got out and undid the caliper brake line bolt. Very little pressure present and not much flow of fluid from caliper. Caliper still very stiff.
Darn - caliper piston stuck in bore. Funny that this occured on both sides and appeared to show up all at once but that was the case.
I reattached the line and pumped the brakes slowly to blow out the piston. Using a toothpick I picked out the inner seal ring and found rust in the groove. Also a lot of black rust/crud was built up on the outer bore edge between the main seal and the outer dirt boot. This I scraped off with a knife. Once cleaned up, the seal easily reinstalled and the piston lightly wetted with brake fluid was installed and movible by hand alone.
Bled this side then found and did the same on the other front wheel. A final brake bleed of both sides found a little more air then all clear.
Overall an easy repair and best part it was only 6 bucks for some walmart brake fluid. Just needed some courage to take the leap and pop out the pistons.
Hope this helps as I was initially stumped by the double front sieze thing.

I would bleed the rest of the brake hydraulic system to get all the old brake fluid out of the system. In order for this to happen, I would guess that the brake system hasn't been bled in some time and the fluid has picked up a lot of moisture. If this problem happens again shortly and you discover more rust in those calipers, you will have to replace both calipers.

Mike

[PortugalFocus]

Originally Posted by Mike Gerber

I would bleed the rest of the brake hydraulic system to get all the old brake fluid out of the system. In order for this to happen, I would guess that the brake system hasn't been bled in some time and the fluid has picked up a lot of moisture. If this problem happens again shortly and you discover more rust in those calipers, you will have to replace both calipers.

Mike

If you do need to replace the calipers, looks like it's a great time to upgrade to ES300/Camry Wagon Calipers or the LS400 Calipers.

How To's and What is Needed:

http://www.toyotanation.com/forum/sh...d.php?t=298359

http://www.toyotanation.com/forum/sh...74#post2693874