Brake problem with my 1997 Toyota 4 Runner

Maintenance/Repairs
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1

For about 6 months I have experienced a problem with my brakes off and on. When I appply the brakes, the back brakes lock up and the wheels grind. In Charlottesville where I attended school at UVA I had it in the shop but they were not able to fix it as they could not get it to do it.

At home in Dallas last week the back brackes locked up and I had to have it towed to a garage here. After looking at the brakes the mechanic discovered that the seals were leaking so he replaced them. He said the brake shoes were fine and he just cleaned them and did not replace them.

The car ran well on a trip to Austin this weekend but just as I got home the same thing started happening again.

Any help or advice you can offer would be appreciated.

Thank you,

Douglas Benson
Dallas, TX

2

If the rear axle seals were leaking, did they check the rear differential fluid level after doing the repair?

If brake friction material gets contaminated with oil/grease over an extended period of time the friction material absorbs this contamination. The only way I know of removing the contamination from the friction material is called sweating the brakes. This requires using an oxy/acetylene torch to heat up the friction material so the contamination is leached out of the friction material. If you try using a simple brake parts clear, this doesn’t penetrate deep into the friction material to remove the contamination. So as you use the brakes and the friction material becomes hotter the contamination starts to leach out. And the brakes grab.

Replace the rear brake friction material…

Tester

3

any time the brake shoes or pads get any kind of fluid(brake fluid or grease)on them they need to be relaced the our cheap inough

4

I agree with Marc but am not sure whether that would necessarily cause locking up.

Did he just replace the seals or did he replace the calipers?

5

I’m unsure from the original description whether or not the back brakes stay locked up when the IO takes his/her foot off the pedal. OP?

If the brakes free themselves when you remove your foot from the pedal, I’d look to see whether the system has a proportioning valve. That’d be an additional possibility to consider. If the valve is inoperable, too much force may be being applied to the rear brakes, causing them to lock up before the front has a chance to share the load. Proportioning valves are there to reduce the amount of force applied to the rear brakes to prevent this condition.