My brother in law called with a problem with the brakes on his truck(96 Chevy HD 1/2 ton), seems one rear drum is dragging and getting hot. It doesn't completely lock up but drags enough that he can feel it when backing up plus it smells like hot brakes smell. He pulled the drum and to him there didn't look any different the the opposite side. Brakes are self adjuster type without access to the star adjuster from the out side. Any ideas why this brake would adjust itself to the point where it would want to lock up, shoes are about 1/2 used up but have about 80 thousand miles on them, fronts are disk and are relatively new... Any thoughts...... Tedd

 

Would check for anything related to the park brake sticking, also make sure the wheel cylinder pistons move freely.

 

One possible cause is that the drum is out of round. I've had this happen with brand new drums, both on my similar year Chevy truck and on my Custom Cruiser. As the out-of-round drum turns, it causes the shoes to move back and forth,which actuates the self adjuster. Turning the drum fixed it in both cases.

 

Joe, normally when a drum is that out of round you can feel it when the brakes are applied.

 

Negative in both of my experiences. The out of roundness simply exercises the shoes back and forth. There was no vibration.

 

I think we have a winner, I'll let you know after either he replaces the drum or turns it. Ain't this a neat forum.... Tedd

 

Don't replace the drum, turn it (or have it checked for runout). In both of my cases, these were brand new (premium grade NAPA) drums that were out of round right out of the box.

 

Back in the day we used to have everything turned, even brand new.

 

I'll pass on the Info...... Tedd