Help, 2000 silverado 2500, front brakes keep locking up after driving
for a while, pedal gets hard, brakes apply, stops my truck, just burnt
up a set of pads, pull over let sit, brakes will be ok again till it
sits again, sometimes its ok for the day, changed calipers-pads-bled the
brakes 3 times with synthetic, fluid does not want to go back up toward
the cylinder when this happens if I jam on the brakes a bunch of times
sometimes it frees up. typical scenario, leave my house to go to work,
after 10 minutes on the highway without touching the brakes, the front
end starts to shake, the truck slows down, the pedal gets hard as a
rock, right up at the top, there is no leaks, changed the drivers front
brake hose, changed calipers but that didnt help, its in the hydraulic
unit or master cylinder.
ABS doesnt seem to work when this is happening, I can push hard on the
pedal and lock the front wheels when this self applying problem is
happening, no prolblems with the rear brakes at all.
This all happened after I put new pads in about 3 weeks ago, they had
60,000 on the old pads with no brake problems whatsoever, the only thing
I can think of is I compressed the calipers with a C-clamp and pushed
the fluid back into the master cylinder, which I have done a million
times before, I was told that this is fine for the GM EHCU system.
Did I mess up the EHCU or some kind of check valve.
I have power steering pump assisted power brakes also.
The EBCM is not running and the ABS does work when this problem is not
happening. I drove around in the snow for 1/2 hour yesterday and made
the ABS works its ass off trying to purge the EHCU, and it was fine all
day, when I went home from work that night the front brakes started
locking up again on both sides, I mean smoking pads.
Billymac in Boston