After sitting overnight or for a few days), the front brakes on my 2002 Toyota Tundra 4x4 lock up when lightly applied while I am moving forward at a slow, driveway speed. When I try to move forward again, the brakes remain locked, sometimes slightly and other times very strongly. If I increase accelerator pressure to force the vehicle to move, the brakes resist, then release with an audible bang. This first appeared in August, after the truck was parked for about 6 weeks.
The sticking is more obvious when the weather is extrememly cold and but it also happens at warmer times. The sticking is less frequent, but still occurs occasionally after I have driven enough for the brakes to be warm from use.
My mechanic has replaced the Master Cylinder, brake lines, parking brake vanes, and the load proportioning valve. He has verified that it is the front brakes, and that calipers and return springs operate freely. We are at a loss as to what to do next. Any ideas?
I’ve never heard of return springs on front brakes? What about your ABS unit creating some kind of hydraulic lock, trapping fluid temp. causing this defect? I’m assuming that’s why he changed the master cylinder.
Sorry about the return springs mistake. I was just trying to say that the front calipers can release freely, so the problem is not that the calipers ‘jam’ closed mechanically and can’t release after the brake pedal is pressed and released.
Did you ever figure out what was causing this problem. My tundra does the same thing.
Disc brake temporary lock-up is often caused by a faulty flexible hose that connects to the caliper. After that, the caliper isn’t freely sliding on its guide pins. Next? … hmmm … well, maybe the caliper piston is sticking in its bore. If the flexible brake hose is known to be good, replacing the caliper with a new one is a common sense next step.
I know some one opened a 10 year old thread. But I have to ask. Does anyone know what “parking brake vanes” are?