rear brakes lock up on 1992 Chevrolet Cavalier

it started with the dr. side rearlocking up,it would do it once in a all the time. 2 wks later the other wheel started doing the same if you just toutch the peddle,both rear wheels lock up.replaced master+brake fluid.what else could it be????

Asked by for the 1992 Chevrolet Cavalier
1 answer
Did you check the wheel cylinders on each brake? Sounds like leaking fluid onto brake linings. Master cylinder wouldn't cause this type problem.