My 88 740 with no ABS and Bendix calipers on the front has been showing substantially uneven wear between the inboard and outboard brake pads on the front driver's side wheel. I've been told that this is a problem associated with something not moving or sliding back and forth the way it's properly supposed to when the brake pedal is pressed and released. I have lubed up the guide pins that the caliper slides on, and they seem to be fine, but the problem hasn't gone away, so I'm beginning to suspect that I've got a stuck piston. The other day I noticed that there was a tear in the dust boot surrounding one of the pistons that went about one-third of the way around it. There was no noticeable damage to the piston, but seeing the tear was pretty disconcerting. How likely is it that the piston with the torn dust boot is the one that is seized up? What is the best way to test whether or not this is the case?
Assuming that the piston is the problem that is causing the uneven pad wear, where do I go from here? Can the piston be replaced relatively easily and reliably, or will I need to replace the whole caliper? How should I shop for new or rebuilt calipers that will last? Doing a little bit of browsing online, I found that autopartsworld.com will sell me a rebuilt caliper for about $60, napaonline.com wants about $55 for one, and carparts.com offers a staggering array of combinations of parts and pieces for lots of different prices. Do any of you know if any of these is any good? Where else, either online or offline would be good places to look for high quality rebuilt or remanufactured calipers? Thanks for the help.