Most surge brake installations include a little lockout control lever
which can be engaged to prevent the brakes from locking up when backing up
If you look at how the servo actuator is designed, they will only
sense the need to apply the brakes when going forward.
Reading the instruction manual is good!
S/V Dynamic Equilibrium
31 May 2001
We have surge brakes that evidently do not have a lock out. If we are
backing up a grade, and we don't disconnect the line, the brakes will
bind up and stop us. If I attempt to overpower the brakes with the
engine, which I did at GB last spring, it will lock the wheels with
pressure on and forward motion is impossible. The only way to clear
the pressure is to disconnect the line an depress the "button" on the
coupling. This allows the hydralic fluid to escape and release the
brakes. Elton showed me what we had to do to escape the perdicament.