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Old 06-23-2010, 11:36 PM   #5 (permalink)
autoteach
Master EcoModder
 
Join Date: Apr 2010
Location: belgium, wi
Posts: 262

Bus - '94 Ford School Bus huge

Stupid - '01 Chevy Blazer LS
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Quote:
Originally Posted by Old Mechanic View Post
If the calipers are sticking you can verify it by breaking loose the bleeder on the suspect caliper, just a little bit to see if there is any residual pressure in the system.

There shouldn't be any, and the caliper will spin more freely if there is any residual pressure.

If there is any residual pressure then you have two possible sources.

Bad master cylinder that is not allowing the pressure created to be released.

Bad front brake hoses, which have swollen shut internally and act like check valves, not allowing the pressure created to be relieved by the fluid moving back into the master reservoir.

If the calipers are or the "floating type" with a single piston on one side and pins that allow the caliper to move when the pressure is applied. When the pins freeze the caliper can not move and it will cause the brakes to stick.

The last problem is the most common when you have the single piston (only one side of the rotor). An additional symptom of the sticking floating pins is uneven brake pad wear.

regards
Mech

+1

On another note that may not be affecting you (as I doubt you have ABS), I had an ABS module that got crystallized brake fluid (OLD!!!) in it that clogged the ports so that it held pressure. It should have been replaced, but the owner would not even buy one from the junk yard. We cleaned it and it worked?! (that is a question/statement). But MECH is right, check those things out.
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