2007 GMC Sierra 1500 Classic SL 6 Cyl 4.30L
Why are my front brakes locking up when temp reaches 90 degrees or higher
driving to work at 5 am, there are no problems with the brakes but on the way home in the afternoon, after the temp reaches 90 degrees, the front brakes start to apply without my help until it almost stops the truck. I then must stop the truck, open the hood, let the vehicle cool off for 45 minutes and I actually hear the calipers slowly release their grip on the rotors. also, today was very hot so when I finally started it up again, now the abs light is on. Help please. By the way, I have disc fronts and drum rears.
The front hydraulic flexible brake lines start to break down internally, and the innermost "tube" starts to flake. The flaking material becomes little flapper valves that will allow fluid to flow in one direction, but not in the other direction.