Dragging disk brakes


#1

1989 GMC van. What causes the front disk brakes not to release completely after taking you foot off? The dragging is causing a lot of heat and touching the disk will burn your skin. Other than reduced mileage is this dangerous, will it cause bearing problems? The brakes do work fine? What is the fix?


#2

A very short list:
-sticking caliper
-brake flex line rotten on inside
-crimped hardline
-bad proportioning valve
-ABS module problem
-master cylinder problem
-caliper bracket misalignment
-caliper slider sticking


#3

Is this dangerous? Yes, the brake will eventually fail . . . maybe no brakes or maybe freeze stuck. The brakes DO NOT work fine . . . you are driving a dangerous vehicle. Forget the bearing issue . . . find a rebuilt caliper (loaded) and change BOTH sides, bleed your brakes, and post back. Busted has posted several other problems which might be the cause . . . my bet is on the caliper. Rocketman


#4

“Other than reduced mileage” - mileage will be significantly reduced, not great in big van already.

“is this dangerous?” Yes, very! Hot brakes will fade. This means when you need to stop your big car it won’t.

“will it cause bearing problems?” Probably. Hot brakes mean hot wheels which means hot bearings which means thinned out grease. Heat and lack of grease is what burns out bearings.

“The brakes do work fine?” Is this a question? The brakes will stop you, but they will not perform well in emergency situations and will not do well going down long hills.

“What is the fix?” Get the brakes examined to find the real problem. The calipers are not releasing the pads off the disks. Could be dirt in calipers and one or several of the items listed by BustedKnuckles above. At the least you are going to need new pads, likely new rotors, and rebuilt calipers and that’s if it is a relatively simple problem. You probably just need a good brake job on the front wheels, and get the rear drums checked out too.


#5

The caliper piston seals promotes piston retraction,weakness here can be the cause of the piston not retracting that little bit it needs to.

I would make sure everything external is cleaned and lubed (cost you only time). Replacement parts would be the rubber hoses,two calipers,and a brake fluid flush(suck all the fluid you can out of the resivoir with turkey baster, refill and let calipers gravity bleed). Dont push any dirty fluid back into the system when you have to push the piston back a little,open the bleeder.

I call any brake concern “dangerous” because I want people to take system problems seriously. Extreme condition,melt the bearing grease.

It does sound like you still have the option of simply re-using your rotors and pads. How about taking this oppourtunity to do a full bearing repack (clean out all the old grease in the rotor hub) and make sure the rears are adjusted fully,whens the last time you checked them?