SkoorbMax

Thanks, I don't think they are bent, but they are definitely a ton "stiffer", either the boot is swollen or whatever. I'm going to have to order a new pair.

SkoorbMax

I think that is it.

I've just put them together for the third time.

a) my hand brake is too tight
However,
b) I am really 90% sure the problem is the grease I was using. I am using some synethetic stuff from advance (permatex ultra disc brake lube). It's safe for rubber parts, but my bottom calipers with the rubber sleeves on them are binding like fvcking mad. Two nights ago I put the brakes together but didn't quite finish. Came back out this morning, the damn things are completly stuck (well, almost; I did get them out). I think that although the grease maybe was "safe" for rubber, it was an extremely poor lubricant for it, so the rubber sleeves on the lower pins (aka bushings) were binding. I cleaned the hell out of them and put some silicone based lube on them and even now I can tell that they are moving like a knife through hot butter.

So, the handbrake after the caliper replacement was exacerbating this to some mild degree, but the main cause was, I think, these pins. If the caliper pulls the pin out while braking and it won't retract, it will cause the pad to drag. Then you end up with a red rotor like I had!

Please, nobody use that green packet permatex lube on their rubber-bushed calipers. I really think that even if it's not causing damage to the rubber sleeves it is a horrific lubricant and this has been a very time-involved lesson for me. Silicone is the win when rubber has to move.