Air Chamber/Spring Brake. Midland Belly/Bottom Dump Trailer 4.6MB, Belly/Bottom Dump Trailer

5.2.11 AIR CHAMBER/SPRING BRAKE

Air chambers mounted on the axle use the air supply/pressure from the tractor to apply the service brakes for stopping the vehicle. In addition this air chamber may be equipped with a spring brake that applies the brake when the service side of the brake loses air. The spring brake side of the system is used as a parking and/or emergency brake if the service side fails.

Spring brakes should not be serviced by anyone in the field unless they have been trained in the proper procedure. Do not open the air chamber unless the spring is caged or locked out. Do not work on the brakes unless the springs are caged or locked out. Do not move the trailer if the springs are caged.

When caging or locking out the spring brakes, follow this procedure:

1. Place chocks in front of and behind the trailer wheels.

2. Insert the release bolt, stored on the side of the chamber, into the hole in the head and through the piston.

3. Turn the release bolt clockwise until it stops and locks.

4. Pull release bolt out as far as possible and run the nut down while holding the bolt in place.

5. Use a wrench to turn the release bolt nut clockwise until the bolt extends about 3 inches.

6. Be sure the release bolt is locked in position.

7. The spring is now caged and the trailer can be moved.

Fig. 73 SPRING BRAKE

8. Always release the spring before placing the trailer back in service.

Schematic

Axle

78