Not to beat this to death, but you still have the problem that the spring brake did not apply. The rear brakes may be out of adjustment. A simple spring brake test is to check if the mh will move with the spring brake applied.
With normal air pressure; On a level surface apply the service brake (brake pedal) then apply the spring brake (pull out the park brake handle), place the transmission in gear, release the brake pedal, apply a small amount of power. THE MH MUST NOT MOVE if it does the brake adjusters need adjusting. Adjusting of the brake slack adjusters is easily done and should be a part of you routine brake check as is the park brake check. Drive safe and keep the blue side up. JT
