Anyone else have the rear(the shoe closest to the bumper) crack on your truck?

They are still pretty thick, but there are cracks in the shoes (both sides the shoe closest to the rear bumper). near the top of the shoe. The forward one are fine.

Any idea what causes this?

Are they cheap shoes, or is this common.

Thanks for any heads up.

 

Poss poor adjustment or lack of lube on backing plate. Cracking normally is caused by excessive heat. Poss. shoe was rubbing inside of drum, Or maybe you do a lot of towing.