Cause of cracked rear brake shoe?

[sprucegoose]

I replaced my rear brakes last Dec, turning the drums and replacing left wheel cylinder. Then in May I started to have some jeking/skidding rear brakes and I found the right rear shoe was cracked accross the middle, right thru the rivited area. I replaced that set with another, thanks to my friends at NAPA for warranty on their product! Now it has happened again, on the same exact shoe...

I do notice that the shoe on the front side of that assembly seems to have significant wear, where the cracked shoe has hardly any... That drum did have a small remnant of the grooves produced by the rivets from that first set of shoes that wore out, but it didn't look to bad to me.

I am probably going to try turning the drum again, if there is enough stock on it. Maybe I should replace the wheel cylinder on that side also...Could it be sticking on one side of the plunger?

I have never had a cracked shoe before on any vehicle, what is the major cause of this?

[maxwedge]

Is the drum discolored like it was overheated, try stepping on the brakes see if that wheel drags when released.

[rhandwor]

Sometimes the manufacturers machine gets out of adjustment and the rivets are to tight.
But the problem with shoe wear you have I would check the springs aren't weak on one side or if your drum is slightly out of round. Also check your emergency brake is properly adjusted.

[sprucegoose]

Well, there really isn't any discoloring as if it were overheating... The E-brake seemed to be in proper adjustment, and the brakes didn't seem to be hanging up when you release the pedal. It definitely was grabbing on that side though. When you pushed the pedal down that was the first wheel to stop spinning when rear wheels were off the ground.

I replaced the shoes tonight and cleaned up the drum again. I switched brands of shoes just in case it was a manufacturers defect. The mechanic that turned the drum for me said it was definitely running out. It took him a couple passes to clean up the old surface.

I also took a grinding wheel to the wear pads that the shoes ride on the face of the backing plate. I put a small amount of high temp lube on those surfaces also. Seems good now, we'll see if it lasts. Next step is to replace the wheel cylinder and a hardware kit with new springs if it happens again I think...

[rhandwor]

I have gotten pads where the shoe on the front pad was in a different spot and I had to file down the edge where it grabbed.

[sprucegoose]

Originally Posted by rhandwor

I have gotten pads where the shoe on the front pad was in a different spot and I had to file down the edge where it grabbed.

So you mean the brake pad material was riveted slighly offset on the metal arc? Yes, I did think about that. It seems to be a non-issue here as they were centered well, and no rubbing on the edges...

Another thing I did notice though. There was a lot of end play in the axle on that side. About .060" in/out. I don't know what the spec is, but could that be causing it also? I am imagining this being hard on the brake assemble when turning and braking simultaniously.

[rhandwor]

I'm not sure of the spec. but they normally have some play. If the metal part of the shoe is rubbing the inside of the drum I would do further checking. I mean the bolt face of the drum or the axle moves out far enough that the seal leaks. The only adjustment I'm aware of is to shim the spider gear pulling the axle horseshoe inwards.

[maxwedge]

Possible issue with the other side not working properly, so other wheel grabs first and/or is being overworked. I don't think the axle end play, if it is .060, should be a problem, usually at that mileage the axle groove and "c" retainer have worn some.