hey guys im tyring to help out a buddy of mine whos 1986 dodge, "not a diesel" 4x4 truck is having brake issues. his truck sat for about a month and then he went to go drive it but when he hit the brakes they wouldn't release and we can't figure out what would cause it, please any help would be greatly appreciated, sorry about this thread not being a diesel topic, but hopefully someone can help any ways.

 

come on guys i know somebody has had this issue or has at least an idea???? pleeeeaaase, just a little bit of help.

 

first turn each wheel if possible, then open the bleed screw on each wheel, if you have pressure something is sticking in the master cyl or proportioning valve, if not the shoes stuck to the drum for some reason like rusting or a part comming off.

 

It's more than likely rust-build up either in the wheel cylinders holding the shoes out or rust build-up in the drum.

By any chance has the e-brake cable been depressed for parking? Cable siezed will cause that too

 

The power brake booster has leak in it and that will make it lock the brakes. You can pull the vacum line and get it to work with very marginal brake action. Not a fix but you can limp it home that way.

 

hey thanks for the replys, guess i should have specified that the brakes are disc, the master cylinder was just replaced a little while ago so i doubt thats the problem. but any more ideas would be appreciated. thanks

 

something is not allowing brakes to release. it's either hydralic or mechanical.

you can try releasing hydralic pressure. but I'd try jacking up one axle at a time first. this allows you to isolate your problem.

you didn't post if all wheels were locking up or just one wheel. a frozen caliper and/or rear wheel cylinder can do exactly what you are describing. so can the proportion valve in BMC not working.

a flex hose collapse can trap pressure too. there's all sorts of possibilities. rear brake shoes almost worn out, can lock up at end of travel. when parking brakes is applied.

losing the vacum booster should not cause lockup. your brake system should work exactly same except for increased pressure needed to operate brakes.

 

woops i keep failing to specify well it is the two front brakes that are clamped on the rotors. and my buddy can drive the truck, but only with lots gas to keep it moving, they locked up on him when he was on the freeway and he braked a little to slow down, but the calipers woudn't release when he let off the brake.

 

that's a little better info...

with both frt's locking up, highly unlikely two calipers will lock up at some time.

now is the time to release a little hydralic pressure to see if both frt wheels release. if both wheels release, then chase down what's causing hydralics not to release.

if after you release pressure and both wheels are still locked up. then both calipers pistons are not releasing.