Abstract: Disclosed is a spring-engaged, pressure fluid-disengaged, parking brake of the disc type which includes an annular piston movable towards and away from the brake discs for engaging and disengaging the brake. The brake housing includes an aperture coaxial with the brake shaft and the piston carries a tapped bore in alignment with the aperture in the housing. A bolt may be threaded into the bore through the aperture and rotated to draw the piston towards the aperture to disengage the brake in the absence of pressure fluid.

Abstract: An air brake control system of high reliability is provided for a vehicle of the type having front wheel brakes, rear wheel brakes, a first brake control element such as a pedal which actuates the front and rear brakes, and a second brake control element such as a pedal which also actuates the front and rear brakes. First and second pneumatic circuit means for controlling the brakes are duplicated back to the outlet of the air compressor in an arrangement where one side of the circuit is automatically isolated from the other to maintain braking capacity if a loss of air pressure occurs on the one side. Means is associated with air streams of only a selected one of the first and second means for providing a function absent in said first and second means.

Abstract: An air brake control system of high reliability is provided for a vehicle of the type having front wheel brakes, rear wheel brakes, a first brake control element such as a pedal which actuates the front and rear brakes, and a second brake control element such as a pedal which also actuates the front and rear brakes. First and second pneumatic circuit means for controlling the brakes are duplicated back to the outlet of the air compressor in an arrangement where one side of the circuit is automatically isolated from the other to maintain braking capacity if a loss of air pressure occurs on the one side. Means is associated with air streams of only a selected one of the first and second means for providing a function absent in said first and second means. A transmission neutralizer is also operated by one of the pedals.

Abstract: A brake mechanism includes a body and a piston movable relative thereto in braking and brake-releasing directions. A spring is disposed within a chamber defined by the body and piston to urge the piston in a brake-applying direction, and pressurized air may be selectively directed to such chamber to the piston in a brake-applying direction.