| Re: New brakes, pad dragging on one side. |
Subject: Re: New brakes, pad dragging on one side. by CentralCoaster on 2015/4/27 19:56:37 Pins are new and lubed, brackets is reman on one side, original on the other. The pin slop feels fine. Hydraulics all checked out. Here's what was happening: I added those H clips when I installed the calipers. Plus the caliper on the driver side is powdercoated. I guess they powdercoat their loaded calipers as an upgrade. I spray painted the bare caliper I bought to match it. The H clip goes in the middle of the caliper where the pad springs push against. Those springs are to keep the pad pushed against the bracket. Problem is, when you powdercoat the caliper there, then add the thickness of the H clip, it compresses those pad springs even more, jamming them hard into the bracket. This force tries to pull the caliper away from the axle, taking up whatever slop the pins offer. All this proceeds to misalign and bind up the caliper. On top of that, the bracket wears where the pad backing plate pushes on it. This wears divots, further hindering free movement. AND, the H clip is very smooth, so the back end of the pad slips around quite freely. All this means the ID of the outer pad never gets pulled into the rotor face. Both pads were wearing at an angle. You can see this effect when you loosen the caliper bolts, and the pads try to push it all away from the rotor. I removed the H clip to relieve some of the spring force, and also filed the bracket contact surface smooth. This side I used an original bracket, and had painted it, so the paint piled on probably made that surface even worse. Now if you're thinking the hydraulic pressure will overcome all that and square it up, well it did somewhat, but the full pad still never touched the rotor until I fixed this. And, when you release the pedal, the caliper floats and tweaks back away from the rotor, and that outer edge of the pad then starts dragging on the rotor. The race pad compounds are probably really aggressive and just with that light drag were able to wear the outer edge of the the rotor surface. |
