Archived Rear brakes stuck full on!

[Steve Robinson]

After recent brake work, including having the proportioning valve (RWAL valve ?) replaced, my rear brakes have positioned themselves in the full-on position, as though the parking brake was fully applied. This has occurred after a few miles of highway-speed driving, resulting in the right rear brake severely overheating to the point of smoking heavily. Could this be a function of the proportioning valve malfunction? I cannot drive the truck, obviously. By the way, the rear brakes were not worked on, just the front. Thanks for the help.

 

[tp0d]

How long ago were the rears worked on? Sure sounds like the mounting hardware could have failed... Did you do a panic stop just prior? Rear pistons dont have a habit of stickin on, at least from what ive seen.

-j

 

[Missouri Mule]

No it is not your proportioning valve. Are you sure he did not have the rear drums off? Seems like the adjusters were put on wrong (backwords) making the brakes adjust going forwad and braking. ( I had that happen to a 78 ford van, put the adjsuter on wrong and I had one back wheel smokng. Took it to another shop and fixed it

 

[Missouri Mule]

No it is not your proportioning valve. Are you sure he did not have the rear drums off? Seems like the adjusters were put on wrong (backwords) making the brakes adjust going forwad and braking. ( I had that happen to a 78 ford van, put the adjsuter on wrong and I had one back wheel smokng. Took it to another shop and fixed it

 

[Missouri Mule]

No it is not your proportioning valve. Are you sure he did not have the rear drums off? Seems like the adjusters were put on wrong (backwords) making the brakes adjust going forwad and braking. ( I had that happen to a 78 ford van, put the adjsuter on wrong and I had one back wheel smokng. Took it to another shop and fixed it

 

[Missouri Mule]

No it is not your proportioning valve. Are you sure he did not have the rear drums off? Seems like the adjusters were put on wrong (backwords) making the brakes adjust going forwad and braking. ( I had that happen to a 78 ford van,a mehanic put the adjsuter on wrong and I had one back wheel smokng. Took it to another shop and they fixed it.

At least it doesn't sound like the valve.

 

[HHhuntitall]

Sounds like the shutoff valve just under the master cylinder... . what is that thing? IT's designed in the case you lose brake lines in front or rear, and then it has a valve that slides one way or the other, to prevent massive fluid loss... They don't really work with slow leaks, but if you really mashed on the brakes with air in them, it could have activated... . It will shut off the lines, and prehaps work like a line lock..... Try plumbing around it and see if your brakes go back to work.

 

[DavidC]

Opening the bleeder will tell you if it is under pressure. Be careful of the squirt. If it is not pressure that would be mechanical with the brake itself.

Dave

 

[HHhuntitall]

Opening the bleeder will tell you if it is under pressure. Be careful of the squirt. If it is not pressure that would be mechanical with the brake itself.



Dave

Very good suggestion. :thumbsup: