Trying to figure out if my caliper is needs replacing or not. Symptom is under very heavy braking (braking from 100+MPH on R-comps) the car will steer to the right on the initial application of brakes, don't really notice any difference under light braking or street driving.

Tried bleeding both front brakes with fresh fluid at the track, did not solve the problem.

Pads are DTC-60 front pads with brake ducts, rears are DTC-30's

All 8 pistons up front can be pushed in freely by hand so I don't believe it is a sticky piston.

On inspection, driver outside, passenger inside, and passenger outside pads all have about the same amount of meat left, the driver inside pad however, appears to only have 2/3rds of what the other pads have.

Last year, I had an unfortunate incident with a caliper bolt coming loose and the caliper came out and lodged itself between the hub and the rim. This happened at low speed (around 15mph) and locked up the front tire, didn't destroy the rim but it did leave a wobble in it and a dent on the inside.

Pictures:









Before I jump to the conclusion that the caliper is simply dead, any other ideas on what could be causing this uneven pad wear (and uneven braking)?

 

Looks like it probably did damage when that bolt came out, from the way it looks its either that piston is sticking in on heavy breaking. I would personally change the caliper. Try to look at the caliper itself closely if its damage where the bolt loosened up. I had a customer that had the same problem and it was the caliper. Hope that helps.

 

the problem suggests over braking or under braking at one of those wheels. go buy a set of line locks at napa (hose pinchers). apply one to each wheel and duplicate the problem at lower speeds. these types of calipers can be tricky. i usually find that it is common for the inboard pad on both calipers to wear about 10% faster than the outboard.

be very careful to test at the same speed - 20-30mph should be fine and try to use the same pedal effort no matter what. you are trying to check for the amount of pulling and the stopping distance.

Just because the caliper compresses "ok" doesn't mean that it is applying force properly. another test would be to remove the caliper and have an assistant slowly push on the brake pedal to check the piston movement. this type of caliper relies on the resistance of one side to apply force to the other. I suspect you are going to find unequal force to the driver outside pistons (will be lower than inboard). basically over using the inboard pad exclusively under heavy braking within that caliper.

Ray

 

Agreed. Sounds like something is wrong with that caliper or one of the pistons in that caliper