on the rear air brakes there is a cilinder with two pipes one small (return -easy broke )and one big (main driveforce )lube the plastic pipe then the brass nuts should turn - it pulls a lever cotter pin and split pin (left hand thread on the shaft) which activates the brakes. replace this as its not doing its job! you should not need to adjust rear air brakes only replace pads. + check there is no water in the tanks and no air leaks
mojo, December 2009