Posted by Greg Coffin [172.68.2.94] on Saturday, August 26, 2023 at 10:38:32 :
In Reply to: Brakes sticking issue. posted by Howard [162.158.62.179] on Friday, August 25, 2023 at 17:01:33 :
A couple questions:
Are you running drum brakes on all 4 wheels?
Are all the brakes dragging? One axle? One wheel?
Have you recently replaced all the flex hoses on the brake lines?
Are you running 10psi residual pressure valves on axles with drum brakes?
You need about 0.020" between the vacuum booster output shaft and the master cylinder piston. Less than that can keep the piston from returning all the way, gradually building up pressure in the brake lines. Most booster shafts have an adjustable tip for just this scenario. It's difficult to measure, but worth the effort.
Heat from the exhaust system can also cause problems, but if you can hold onto the brake lines after running the truck for a bit then the problem is elsewhere.
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