that has an odd problem. It seems I have uneven pad wear that is causing a very slight grinding sound and there is a slight feel of the contact at the steering wheel. At first I thought it was the wheel bearing & replaced it. Then I thought it was a bad axle & CV joint. Replaced that. It now appears that the inner brake pistons are putting more pressure on the inner pads than the outer ones. When I took apart everything it became quite apparent what the problem was.
I have bled the front caliper, taken out the pads, put them back in, pushed the brake pistons in on both sides and took every precaution but I still seem to have a brake piston imbalance in this caliper. Does anybody have an idea what the problem is. It doesn't affect the braking performance, it's just that annoying slight grinding problem and the feel of it at the steering wheel. I have checked the other front caliper and it shows no similar problems. Both sets of pistons show force is being put on the pads equally. No imbalance at all. In fact with problem caliper it had gotten so bad that the small studs that signal low pad wear in these Porsche calipers were showing signs of slight rotor contact on them! Not good.

They will atleast be able to pull it apart and see if there are other issues while they are at it.

Hydraulic brake pressure usually overcomes any drag, and the pad will still provide effective braking. However, if the pad doesn't release completely without brake pedal pressure, the pad drags and wears prematurely as in the pic.

<img src="http://pictureposter.audiworld.com/68260/dsc00325.jpg">

I rechecked the caliper last nite and the outer pistons are not pushing out as far as the inners...grrrrrrrrrrrrrrr!!!

Paragon Products for one carries rebuild kits, pads, shims, etc...<ul><li><a href="http://www.paragon-products.com/">Paragon</a></li></ul>

has done it before to rebuild it for me,

take out the pads. Push in all the pistons, then have some one push the brake pedal down 1/4, watch how the pistons come out, &amp; see if they move a little back in.

You may have a sticking piston. If so, just buy the $20 rebuild kit, &amp; rebuild the caliper. There super easy.

What happens some times, is people run a long time with worn pads, this pushes out the pistons out more, over time the piston gets a grove or rusts. Then when you put in new pads, this messed up part can get stuck or stick in the caliper.