sqeek in rear

[snohunter]

on a ride this weekend devloped a squeek in rear.my question is do the brake pads have wear sensors like cars do cause it seems like it only does it at low speeds like in parking lot and not all the time if i touch the brakes it goes away.could it be the pads or am i looking somewere else.and does the rear wheel need to come off to change pads. bike info is 2000 tourer with 25000 on her. from what i can see the pistons on caliper look to be out some. thanks for your help        jeff

[BF]

Could be just brake dust build-up.  Not trying sound like a smart a$$ or anything, but try washing the bike and see if it goes away. 

[Hoser]

Left rear wheel bearing?  Had similar symptoms on the way to IZ10, did not take long to be sure, left hand slow speed turns.  Hoser