2011 XT Brake Pad Pin Rubbing
The rear outboard brake pad retention ring experiences a great deal of friction when traveling along the pin that holds the pads in place. I've sanded the pin and tried lubricating it very lightly. The lever feels terrible, absolutely crunchy, in the first few millimeters of travel but then gets better towards maximum engagement of the brakes.
My eyes aren't good enough to detect whether the pin is warped, but that is my suspicion.
Has anyone else experienced this problem? Is it a warranty issue?
Your description sounds more like a sticky piston. You could try taking both brake pads out, and gently squeezing the lever while watching the pistons. Do you still feel the crunchy feeling in the first few mm of lever stroke without the pads installed? Do the pistons move smoothly at the same time? Make sure you don't pull the lever to the point that the pistons come out of the caliper when trying this.
If things don't work smoothly without the pads in place, try using some finish line chain lube on the pistons, and then work the pistons in and out a few times by pulling on the lever and then pushing the pistons back into place with a 10mm wrench. Do this a few times.
If that solves your problem, clean the inside of the caliper off with isopropel ETOH on a clean rag, pushing the rag inside with a screwdriver. Failing to do this step could contaminate your pads.
Hope this helps.
I've lubricated the pistons with shimano mineral oil several times, and they are moving fine. I can actually pull up on the pad and it eliminates the problem. Maybe I'll just rig some sort of spacer.