C15A brakes jamming

[rob love]

Adjustment of the master is critical, as has been mentioned. Another possibility is the collapsing of a flex line internally. They will allow fluid to go to the cylinder, but not back again. If it is the line to the rear axle assy, then both will lock on. To find this out one has to raise the vehicle and determine which wheels are dragging. But again, on a 12 year old rebuilt system that did not get a lot of use, the cylinders would be my prime suspect.