Finally licked the cooling problem - now it's the brakes
OK, here's the situation (for the last four race weekends) - bleed the brakes before a track session, good firm pedal for a few laps, then the pedal gets "long" (more travel to get the brakes working) - I can pump them up with couple of jabs but this means crappy braking points because I can't left foot brake while still accelerating due to my pedal arrangement/big feet.
If I take some slow laps with light braking, the pedal firms back up.
If I come in, with the long pedal still present, and watching the balance bar indicates it's always the rear that's the cause. We bleed the whole system again, getting a couple of tiny bubbles at the rear at most - back out, same thing all over again.
The pads are PF 83 or 101's (supposed to be the same, since 83's are now NA) condition- fronts are fresh, rears are three weekends old, but still plenty thick. Wilwood single piston fronts and one, two piston rear (on a spool). Solid (3/8th ?) rotors - measured only .004 runnout on the rear (looking for piston push back) some evidence of fluid being pushed out of the (rear) MC. MC's are relatively new and seem to be working fine - we have changed them around, trying different sizes for different feel, but still had the same problems. Caliper temps have never exceeded 400 degrees.
Any ideas?
Clark
When it's good, the braking is very good, with nice "feel" .
OK, here's the situation (for the last four race weekends) - bleed the brakes before a track session, good firm pedal for a few laps, then the pedal gets "long" (more travel to get the brakes working) - I can pump them up with couple of jabs but this means crappy braking points because I can't left foot brake while still accelerating due to my pedal arrangement/big feet.
If I take some slow laps with light braking, the pedal firms back up.
If I come in, with the long pedal still present, and watching the balance bar indicates it's always the rear that's the cause. We bleed the whole system again, getting a couple of tiny bubbles at the rear at most - back out, same thing all over again.
The pads are PF 83 or 101's (supposed to be the same, since 83's are now NA) condition- fronts are fresh, rears are three weekends old, but still plenty thick. Wilwood single piston fronts and one, two piston rear (on a spool). Solid (3/8th ?) rotors - measured only .004 runnout on the rear (looking for piston push back) some evidence of fluid being pushed out of the (rear) MC. MC's are relatively new and seem to be working fine - we have changed them around, trying different sizes for different feel, but still had the same problems. Caliper temps have never exceeded 400 degrees.
Any ideas?
Clark
When it's good, the braking is very good, with nice "feel" .

















