waddisme

Currently stock Z06 calipers with 62k mi (~25 track days) and XP12 pads. Severe straight-line braking on flat surface all is good. If there is the slightest wheel turn or bump or any kind of balance change, it feels like the pads lose their grip and car gets unstable and seems to lose stopping momuntum. Pedal feels like ABS kicking in, but DIC says nothing. Fluid is ATE (fresh) and caliper pins have been greased. It has done this with XP10s and the XP12s. Seems like it started about this time last year. Doing RD ATL Sat, so I can try different things if it helps. I am relatively easy on brakes - only drive about 7/10ths. Hell I even still have the rubber dust covers on my calipers.

Thoughts?

RX-Ben

Wheel bearings are good?

waddisme

There is no movement from 9-3 or 6-12. Is there a better way to test?

sperkins

Doesn't sound like a braking issue to me. Have you had your setup change recently or have you at least checked your toe?

waddisme

Nothing has really changed other than going from stock sways to Pfadt HD and back to stock. It seems to occur with my R80s or my BFG KDs. Alignment was done by David Farmer about a year ago. That is all that has really changed.

0Louis @ LG Motorsports

Recheck the alignment, and check diff pre-load. Bushings do funny things over time

waddisme

Whatever the issue is, it is getting worse. Did VIR this weekend with instructor, so I pushed car pretty hard, including brakes. My instructor was trying to get me to use brakes to help turn car in like T1, T4, T12 etc. Once they were hot, just tapping them felt like the rf was sticking. Bought some stock C5 calipers and sending to Randy at DRM to have ss pistons and seals done. Even if not the issue, it will be a nice upgrade. Will just have to paint C5 calipers. I thought it would be safer to get C5s seeing the Z06s had more of a chance of being abused. Hopefully this will cure the issue.

sothpaw2

Naaaaw--the conventional wisdom here is that the C6 caliper is less likely to spread (will last longer before spread). I went with a C5Z caliper though because I didn't want to have to mess with the paint. It's GM torch red by the way. There's a company that makes hi-temp caliper paint but I think they want $100 for the TR paint (they have it pre-made since it's a common GM color) w/applicator (only way its sold). I forget the company name--do a search in C5 tech & C5 Z06.