I have seen this discussed before, but cannot find it again. Brakes staying on> It's the 57 GMC 2 1/2 ton.
I had them working perfect, everything new, including new hydrovac. Now all of a sudden the rears are not completely coming off. The pedal feels hard too. They are holding the truck back when driving, and I cannot turn either side by hand with engine off and jacked up off the floor.. I have backed the adjustments off about 6 clicks and even opened the bleeder at the master cylinder on the hydrovav. It squirted some fluid out, like the hydrovac was still applying pressure to the rears. Still cannot turn them by hand. The fronts turn freely. Has something happened to my new hydrovac? I have not even drove it out on the road but a couple of times.