[Robby]

Ug.....rear disc systems always seem to have issues like this.

My first thought is the caliper slide pins are corroded (with the outside chance of the caliper piston itself).
In the case of the pins, (slides) hydraulic pressure (brake application) can apply the brakes but pin corrosion prevents the caliper from fully releasing. This causes the affected side to wear the pads rapidly.
As the corrosion advances, the side with little or no binding, applies when the pedal is depressed and the bound side just goes for the ride.
This explains the rusted rotor on the high wear side.

Here in the salt belt, I find myself freeing/lubing bound caliper (and pad backing plate) slides every spring on my sons service vehicles that have rear disc systems.
A combination of road chemicals and little heat production (rear brakes only do about 10 to 20% of stopping power) are, imo, the culprits.

So, sometimes the piston itself does corrode in the bore but the vast majority are bound by the slide pins or the pads are bound in the carrier bracket.....always corrosion.

Last year I began a annual clean and lube maintenance on his equipment just to preserve rear pads and rotors. Prefer to replace brakes for normal wear, not created wear.

I have concluded that as we see more and more rear disc systems this will become a suggested service practice (clean/lube) every year or two.

Rob

 

[Robby]

My dad had a thing against disk brakes. He said drum brakes were designed to prevent problems with contamination.

I don't know if they were designed with that intent......more of a result of the systems design.
I had a similar discussion like this on the Miata forum....a member was whining about the complexity of the rear drum brakes he had recently replaced. That turned into a 'what system has the most problems' discussion. Miata's are notorious for binding their rear caliper slides and most owners consider 'disassemble/clean/lube' part of their annual service routine.

The posters that did have daily drivers with rear drums were essentially unanimous in their reporting of no troubles, regardless of where they were operated.

Rob