I'm at wit's end trying to solve the problem. I had the calipers powder coated a different color and after re-assembly what's happening is one of the outside guide pins is rubbing the rotor and actually scoring it. I have had the calipers off 3 times now.

It appears the inside pistons are pushing out fine but the outside pistons (one on the logo side) are not. First time I removed the calipers I blocked off the inside pistons and used air pressure to make sure the outside pistons were moving out - they were so I compressed them back in and re-installed the calipers. Followed the service manual bleed procedure every time and had good fluid flow out both sides of the caliper. After bleeding, the rotor turns freely but when I put the wheel on, and tighten it snugly the rotor is bound up and I can turn it slightly (with great force :-)) but can hear the grinding when I attempt to turn it.

This happens the same on both sides - the outside guide post rubs - actually binds against the rotor.

The second time I took the calipers off I removed all pistons and picked the best six from the old ones and installed those on the outside and made sure they seated easily. Re-installed and after bleeding the rotor turned freely w/o the wheel on. However, after putting the wheel on and snugging up the bolts the same problem existed.

The third and last time I took them off I kept the brake line connected and clamped off the inside pistons and had my son press slightly on the brake to see if the outside pistons were moving - they were on both sides. Depressed the pistons enough to re-install but still have the same problem. I'm using Hawk HB531Z570 and HB532Z570 brake pads. When I look at the top of the pads with the calipers installed and bled, it appears the inside pistons are pushed out about 3/8 of an inch or so but the outside pistons don't appear to have pushed the pads out at all.

2008 Z06 3,500 mi.
Original calipers
Original rotors
Original bolts 129 ft lbs torque
Inlet fluid bolt 33 ft lbs torque

Have you ever heard of this before and if so what is the solution - it's driving me nuts!

Thanks for any help you can give me...

 

Call 209-533-1453 ask for Dan tell him I told you to call. Dan has just taken apart 12 Zo6 calipers and have found diffrent tolerance on most of them he should be able to help you.

 

Thanks Carbotech adam!...called Dan and got a fantastic explanation and a solution to try. Dan if you read this, thanks so much for your time!

 

I always like to help, if I can. And it was funny I saw this and right away Dan poped in my head. I hope it works out for you and as always I will be happy to help you with a set of pads if you need.