There's a few common causes of this. Some expensive, others not so much. The best suspect is a constricted front rubber flex hose. The photo below shows the hose, and the arrow is pointing to a metal bracket where rust can build up inside to squeeze the hose closed. You can force brake fluid through it to apply the brakes, but the fluid can't return on its own. That makes that brake drag, building up heat. That heat migrates into the brake fluid causing it to expand and apply that brake even harder. One big clue is the brake pedal will be higher and harder than normal.
To verify this, loosen the soft metal line nuts at the master cylinder about a half turn each. If brake fluid spurts out and the brakes release, we have more serious problems that we can discuss later if necessary. If the brakes do not release, retighten those nuts, then go down to the caliper that's getting hot and locking up. When this occurs, stop on a slight incline, shift to neutral, place a block about a foot downhill of one tire, then crawl underneath and open that bleeder screw. If the brake releases, suspect the rubber flex hose for that caliper. On other brands that crimped bracket can be opened up a little with a large pliers, but on yours, that's a real difficult job because it's so big.
The additional clue here is only one front brake will be getting hot when the problem occurs. If both front brakes do this at the same time, they are likely to release when you loosen the lines at the master cylinder. For that, the most common cause is brake fluid contaminated with a petroleum product. That gets to be a real expensive repair and may cost more than the truck is worth. Let's hope it doesn't come to that.
Let me know if this works.
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Wednesday, July 20th, 2022 AT 5:21 PM
