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do u guyz encounter uneven wear of the pads...?? n i mean the 2pads on the same housing...mine seems wen 1 totally almost wear out the other half onli wears 1/3 or 1/2 onli....tis goes to all the 3 housing..btw mine is a brembo

Wots wiv de tex messige langwidge?
Here's an answer in English;
You most likely have sticking or seized pistons.
Strip the calipers, clean everything, check for corrosion/damage. Replace seals if necessary. Reassemble with new pads. Bleed brake fluid. Might as well put new fluid in at this point.

Phil

I would expect this to arise on the rear where there is only a piston on one side (i.e. one pad touches first and then slides the yoke across for the other pad to touch - so one pad will wear more). Indeed the new pads from BMW recognise this and they come with one thicker than the other.

For the fronts however, both pads should touch simultaneoulsy so should wear evenly. As suggested, you probably need a strip down and clean of the calipers. You'll be amazed how much sharper the brakes feel afterwards.

If you dont have the skills to do the strip down, a half way house that can often see major improvement is to leave the caliper connected to the hydraulics and press the pistons out slowly by applying the brakes. You'll find that some pistons move and others dont. Use your fingers or some QuickClamps to keep the easy moving ones in place so you can force the sticking ones to move. A few cycles of moving them out and then squeezing them back in, combines with lashings of aerosol brake cleaner can often get all 4 pistons moving easily without having to interfere with the hydraulics. (So long as you don't accidentally push a piston out too far).

You should thank your lucky stars you don't have the later Tokico made "BMW" calipers because they start furring up/gumming up at the first hint of inclement weather.

mdouglas wrote:If you dont have the skills to do the strip down, a half way house that can often see major improvement is to leave the caliper connected to the hydraulics and press the pistons out slowly by applying the brakes. You'll find that some pistons move and others dont. Use your fingers or some QuickClamps to keep the easy moving ones in place so you can force the sticking ones to move.

Yep do this with lots of brake cleaner sprayed on. I use two pieces of wood, one with a piston wide slot cut out so only one piston can be pushed out with the brake lever at any time - but the slot should not be deep enough for the piston to pop out.

I had the same sympytom on my first S. At least one piston per caliper was siezed solid and the others were not loose at all. The above method sorted it. Some monkey before me had tried freeing them up with a screw driver which only put holes in the pistons. When clean, dem pistons can be pushed back flush using finger pressure only.

how far should the piston be allowed to push out before it is too far?

cc mac wrote:how far should the piston be allowed to push out before it is too far?

Not too far - don't ask

Can't remember exactly but about 10mm or so. Enough to have a good go at them with the missus' toothbrush and some brake cleaner.