| New brakes, pad dragging on one side. |
Subject: New brakes, pad dragging on one side. by CentralCoaster on 2015/4/24 23:17:09 I'm frustrated here after doing a brake job on my 85, maybe you guys have an idea I haven't thought of yet. New rear rotors (EBC) New rear pads (Hawk blue, track compound) New rear hoses (Russell SS) Reman rear calipers (Centric) with new pins and pistons. Adjusted parking brake Also new front pads, cleaned pistons, new bleeders, fluid flush of course. The pads were not dragging before this. I did all this simply because the rear rotors were worn past the minimum thickness, and the calipers were corroded and about frozen on one side, I think causing the pedal to feel sticky when really pushing on it. The rotors came fully painted, but I figured I'd let the pads burn it off. I'm getting a ton of dust on the left rear wheel, audible noise while driving from that corner at least, and the rotor is wearing, yet the inner part of the swept area hasn't even burned the paint off! That was my first sign. I pulled the pads off that side and they're already tapered as if it's a spread caliper out of the box. I measured though, and it seems flat. The taper is very visible but only measures a few hundredths. The previous pads had taper also, even on the front wilwoods, but I figured it was just from hard braking at the track. Also the Hawk inner pad is thinner than the outer, although they weren't even out of the box, which I think is bizzare. Seems to be a lot of wear considering I've only driven it about 6 times since doing the work, albeit trying to do hard braking where I can. I didn't even attempt to bed the pads yet because of the odd initial wear. Engaging the parking brake slightly more doesn't change the noise, so I doubt that's it. There were no issues during install with anything fitting. That particular caliper was an 84 application btw, but it's the exact same caliper as 85 according to GM's parts book, it just came with a different bracket. (They didn't have the bare LR 85 caliper in stock) I guess I can keep driving it until it finally starts contacting the inner surface of the rotor and see how bad the taper is. Even if nothing lined up, it shouldn't drag. The pads are also very aggressive, but they didn't drag before. What prevents the from dragging normally? Do the pistons retract a little when you release the pedal? During bleeding I had to be careful not to get squirts from the reservoir, but that tells me the port is open fine. I honestly don't remember if both reservoirs squirted though. (85 has separate front/rear reservoirs) I suppose it's possible for the front port to open, but not the rear? I did not adjust anything there, maybe something moved during bleeding, I could feel in the pedal the valve being exercised when bleeding the brakes, Such as when you bleed the rear while the front is done. I don't remember how that's supposed to feel, but it was a little sticky at the end of travel. Or does spring steel corrode in brake fluid? I used a different bias spring years ago and haven't checked it since, maybe the whole combination valve is corroded to hell. Are the DRM springs different material or something? I figured all the springs had to be pretty similar in metallurgy, I believe stainless for example is too weak to use for springs. I didn't use the DRM because it was too weak to correct my bias with the large front brakes. Maybe I overfilled the reservoir during refill and the cap is exerting some tiny pressure on the fluid? I have more time to ponder stuff than I do to wrench apparently. I just figured it'd be an easy job. I know there are 93 things that can go wrong, but damn it worked pretty good before I touched it. WWCGD? |
