E 46 Occasional Vibrating Brakes

[OldWolf66]

Hey Folks

I have recently had a strange problem creep up with my brakes. Usually near the beginning of an errand my brakes begin to vibrate, sometimes a lot. It happens under light to moderate brake pedal. When I push down harder the problem goes away, usually until the end of the errand. Has anyone else had this problem?

I put new rotors and pads on about a year ago, but this recent development is the first time it has happened. I bled the brakes all around again, but that didn't help. I checked for leaks and there were none. I wonder if the pads are not moving evenly when the brakes are first applied. But checked the caliper piston and it seemed to move in smoothly and there were no funny wear marks on the metal top or sides of the pad.

I can't figure it out. Is there anything else to check on the other wheels? If nothing else is amiss there would rebuilding the offending caliper be good enough? The cost of a rebuilt caliper from Bavarian Auto is not too much and maybe the right way to go, but I would like to be sure of that before ponying up the money for the caliper and pads.

Thanks

Nick