Archived Rear brakes wont release!!

[Ted Constantine]

So, 2001. 5. If you apply the brakes the rears do not release. Turn the truck off and they slowly over a short period of time release.



Pulling the ABS fuse has no effect.



Pulled the master cylinder away from the booster and the booster appears to work correctly but maybe releases a little slow. (no one has ever looked at a hydro booster work without the master to know what it should do)



We are at a total loss.



Anyone heard of this? Anyone had a hydro booster go bad? The local dealer (high volume) says they have never sold the part.



HELP

 

[Joe Mc]

[font=&quot]This is a repeat from similar thread that I posted to just a few moments ago, may be helpful?

I had a sticky front right on another car some time ago. Replaced all kinds of stuff until I was told to replace the brake hose. Snap! that's what it was. The rubber cracked inside the hose creating a "flap" (or effectively a check valve) this wouldn't allow fluid return and held the caliper from releasing. If it is both rears that are staying applied it could be the hose from the frame to the rear housing?[/font]

 

[Ted Constantine]

interesting thought but then way would the brakes only release when the truck is off? i guess maybe the question is why would the brakes release at all, what does the engine have to do with it. This really has me leaning toward the booster because of the hydraulic pressure being turned on and off.



But, the booster seems to work fine with the master off

 

[LOtero]

Check your hose to the rear brakes. If the booster is bad then all 4 would be staying applied. there is no split at the booster only the master cylinder. with the engine on the booster is always "charged". maybe with the engine on its keeping equal pressure to the rear channel so it wont bleed.

after time if there is a restriction then it will bleed back out, but your description of the problem sounds just like a bad hose. just pull it off and try to blow through it.

 

[Joe Mc]

just pull it off and try to blow through it.

Very Good - Just make sure to blow through both ends.