Brake Issue

[e170drvr]

Hoping some of the experience on this board can help me with this one. what would cause one brake pad to wear considerably more than the other pad in the same caliper? Replaced the front wheel bearings this weekend, and noticed the drivers side outboard pad is almost to the metal while the other is mildly worn. both pads on the pax side are slightly worn like the inboard drivers side. The car does not pull noticeably, maybe slightly to the left. The braking action is noticeably degraded. I have not had a chance to look at the rears, in case it is doing only the left front and right rear only. My guess is a sticking piston on the pad that is worn bad, what do you guys think?

Thank you,
Eric

[fredmeister]

Remove the pads and try cycling the pistons by placing a thin wood shim in place of the pad and pressing on the brake pedal....you basically want to move the pistons in and out all the way without having them blow out of the caliper. You should notice a stuck piston when trying to press them back into the caliper.
I dont think the 930 calipers are as prone to sticking since the pistons are bronze and less likely to corrode like steel pistons.
Good luck and change the fluid while in there.

[A930Rocket]

I don't think the pistons are bronze, but Fredmeister is right about the problem and testing it.

I've pulled pistons out and with brake fluid used a real fine wet and dry sandpaper, clean the pistons and the bores. Clean with brake fluid and re-assemble with new brake fluid to help fit together.

[Miguel Antonett]

One of the pistons is sticking, try cycling them. Remove disks and place a piece of wood instead and apply the brakes, cycle few times... find out which it is and follow 930Rocket's advise.