Rear suspension (Air springs): Description and operation

Air springs

1 Top plate 2 Voss connector 3 Air bag 4 Piston

On vehicles without SLS, coil springs are used. On vehicles with SLS two air springs are fitted between the chassis and the rear axle to replace the coil springs. Each air spring is located at its base on a fabricated platform on the rear axle. The top of the spring locates in a fabricated bracket attached to the outside of each chassis longitudinal.

The plastic base piston is recessed with a boss with two lugs moulded in the centre for attachment to the axle. The piston is secured by locating the lugs in a slotted hole in the axle platform and rotating the spring through 90°, locating the lugs in the slot. The plastic top plate has two grooved pins which locate through holes in the chassis bracket. Two spring clips locate on the grooved pins and retain the top of the spring in position.

Each air spring comprises a top plate, an air bag and a base piston. The air bag is attached to the top plate and the piston with crimped rings.

The air bag is made from a fibre reinforced flexible rubber material which allows the spring to expand with air pressure and deform under load. The top plate comprises the two bonded grooved pins and a female Voss connector in the centre. The Voss connector allows for the attachment of the air supply pipe from the air supply unit. The piston is also made from plastic and is shaped to optimise the springs characteristics.