Rear brakes wear out prematurely/overheat

[rockola1971]

Any updates @Curlyface ?

Legend has it....He is out in the fields somewhere still trying to get stopped!

 

[asand]

Is the diff oil full? could be the axle bearings getting hot.

 

[MassHoe04]

Is the diff oil full? could be the axle bearings getting hot.

I am still learning the GM platform and could be way off, but...
I don't think diff oil is supposed to be making it past inner axle seals to lube axle bearings.
I would expect rear diff fluid to stay in the pumpkin where it belongs.

A frequent scenario that does happen a lot is:
If a caliper locks up and over heats the rear rotors (or drums if so equipped), the red hot rotors transmit the heat to the axle shaft which can sometimes get hot enough to melt the outer rear axle seal and might actually cook the grease out of the rear axle bearings. Then bearings burn out and and seals need replacing.

Sometimes you get lucky... Like I did!
Bearings and seals managed to survive glowing red rotors when my calipers locked up with new pads and rotors I just put in.
The caliper pistons had been so far out for so long, there must have been corrosion building in the cylinders behind them.
When I pushed the pistons in to make room for the fat new pads, the pistons would move out but not back in to release the pads.
Managed to save pads and rotors, believe it or not! Replaced the calipers and was back in business.

 

[972sparky]

Last time I had a rear brake overheat issue was on a used Avalanche I bought. I thought maybe the pins and sliders needed lubed so I took them apart. It ended up being that the “mechanic” who had put some new pads on had put the two inboard pads on one side and the outboards on the other. The side with the 2 outboards was the problem side as the locator lugs on the back of the pad had mashed into the edge of the the piston face and made the piston hang up and not retract into the bore. Installed new calipers and shoes at that point. I also had some issues with the stabilitrack applying the brakes during hard rain to the point of smoke/steam from the rotors. I replaced the speed sensors and did not have it happen again while I owned it. I think the heat from the brake issue may have affected the sensors, they are plastic and close to the end of the axle tube.

 

[rockola1971]

I am still learning the GM platform and could be way off, but...
I don't think diff oil is supposed to be making it past inner axle seals to lube axle bearings.
I would expect rear diff fluid to stay in the pumpkin where it belongs.

A frequent scenario that does happen a lot is:
If a caliper locks up and over heats the rear rotors (or drums if so equipped), the red hot rotors transmit the heat to the axle shaft which can sometimes get hot enough to melt the outer rear axle seal and might actually cook the grease out of the rear axle bearings. Then bearings burn out and and seals need replacing.

Sometimes you get lucky... Like I did!
Bearings and seals managed to survive glowing red rotors when my calipers locked up with new pads and rotors I just put in.
The caliper pistons had been so far out for so long, there must have been corrosion building in the cylinders behind them.
When I pushed the pistons in to make room for the fat new pads, the pistons would move out but not back in to release the pads.
Managed to save pads and rotors, believe it or not! Replaced the calipers and was back in business.

What inner axle seals? The only seals on the axle are at the end of each axle tubes. The support bearings for the differential do not have seals behind them. When you turn a corner or get on unlevel ground the gear oil comes out of your differential (not all) and works its way down the axle tube to your inner and outer axle bearings to lube them. When you change axle(s) you should recheck your differential gear lube level shortly after driving it after the rebuild and top off accordingly since some of the gear lube will wet the new axles and the axle tubes.

 

[MassHoe04]

What inner axle seals? The only seals on the axle are at the end of each axle tubes. The support bearings for the differential do not have seals behind them. When you turn a corner or get on unlevel ground the gear oil comes out of your differential (not all) and works its way down the axle tube to your inner and outer axle bearings to lube them. When you change axle(s) you should recheck your differential gear lube level shortly after driving it after the rebuild and top off accordingly since some of the gear lube will wet the new axles and the axle tubes.

Well... There ya go! I did mention that I am still learning GM every day and this is great information. Thanks for the explanation @rockola1971

 

[Matthew Jeschke]

I am experiencing something similar. Was this ever figured out? My rear breaks are HOT and fronts like I hardly even used them. I have yet to take apart the parking brake. It's the disk brake setup.