I had four tires put on the 300e last weekend, and the tire guy said that my passenger side rear brake pad is shot and I need to get it fixed pronto. He said he suspected a frozen caliper.

Now, I bought this car about 30,000 miles ago, from my dad, and he replaced the rear brakes right before he sold it to me. Is it possible he goofed something up and that's why this one pad wore out so fast? The front pads and driver's side rear are all in better shape.

I am replacing all four pads anyway (none of them were in that great a condition). What's the easiest way to tell if the caliper is no good? Also, what exactly is involved in rebuilding a caliper, if I find that it is necessary? should I just buy a rebuilt one (about $80)? How do I check if the master cylinder is still good?

I already did a search on this, but surprisingly I found little info on actually diagnosing a caliper problem and rebuilding it, only info on changing the pads.

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