wtf is with them?? Know idea what I mean, wait for a nice rainy cool day, then try to drive. Tap the brake and feel them back brakes lock up. All 4 Chevy trucks I have owned have done this. Is it a sign the wheel cylinders are going bad or what? I've been told by someone who works on Chevy fleet trucks day in and day out that its common. I usually push the pedal to the floor a couple times and they loosen up. By the way I've owned an 84, 89, 95, and 97 and they've all doen it at one time or another, though the 84 did it more than the rest.