Rear Suspension

Description
General
The rear suspension comprises two MacPherson strut dampers with coil springs and two sets of three links (known as "trapezoidal links"). A rear subframe is bolted to the body and provides the mounting points for the fixed and adjustable links. The third link is known as the trailing link and is attached from the hub carrier to the body.

The suspension is designed to allow longitudinal movement of the wheel, which allows the wheel to move rearwards and upwards in response to surface undulations. The longitudinal movement allows the springs and dampers time to react to surface changes and improves ride quality.

MacPherson Struts
The left and right hand dampers are handed but otherwise similar in construction. The rear dampers are similar to the front dampers but have slightly different damping characteristics.

The damper body is fabricated from thick walled tubing and has welded brackets for attachment of the hub carrier.

Two smaller welded brackets provide for the attachment of the brake hose to the brake pipe and the ABS sensor cable.

Each damper is fitted with a coil spring. The coil spring locates in a fabricated seat and is retained in a compressed condition on the damper by a top mount and nut. The top mount is fitted with three studs that locate in mating holes in the inner wing turret and retained with three self locking nuts. A bump plate is fitted which accommodates a spring aid. The bump plate is sealed against the inner wing turret to prevent the ingress of moisture into the interior load space.

The spring rates differ between the front and rear suspension.

A spring aid and a bump cup are fitted to the damper to prevent shock loads when the damper is fully compressed.

A dust cover prevents the ingress of dirt and water to maintain the integrity of the chromium plated damper rod.

The damper functions by restricting the flow of a hydraulic fluid through internal galleries within the damper. A chromium plated damper rod moves laterally within the damper. As the rod moves, its movement is limited by the flow of fluid through the galleries thus providing damping of undulations in the terrain. The damper rod is sealed at its exit point from the damper body to maintain fluid within the unit and to prevent the ingress of dirt and moisture. The seal also acts as a wiper to keep the rod outer diameter clean.

Trapezoidal Links
Three links make up the trapezoidal linkage. The fixed transverse link is fabricated and is not adjustable. The adjustable transverse link comprises a tube, threaded at each end. A threaded fitting is screwed into each end of the tube and locked with lock nuts to a prescribed distance between centers. Each fitting has a pressed bush installed. The trailing link is fabricated and is not adjustable.

The fixed transverse link is bushed at each end and is located in the forward mounting of the rear subframe and the forward attachment on the hub. The adjustable transverse link is also bushed at each end and is located in the rearward mounting of the rear subframe and the rearward attachment on the hub. The fixed transverse link and the adjustable transverse link are attached to the rear subframe with individual bolts and nuts and are attached to the hub with a single bolt and nut with a washer at each end.

The trailing link is bushed at one end. The bushed end is located in a separate bracket that is bolted to the body.

The link is secured with a bolt which screws through the bracket into a captive nut in the body rail. The opposite end is forked and locates over a bushed lug on the hub and secured with a bolt and nut.

The fixed transverse links, the adjustable transverse links and the trailing link have a significant role in the vehicle handling. The bushes in each link control the longitudinal movement of the wheel due to braking, acceleration or surface undulations.

The adjustable transverse link allows for the toe-in of the wheel to be adjusted if necessary. The fixed transverse link is slightly shorter than the adjustable link which promotes a small amount of toe-in during cornering. This also minimizes the effects of bump steer. The bush attaching the fixed transverse link to the rear subframe has a very soft initial movement rate that becomes progressively harder as the rate of deflection increases. The three remaining bushes in the fixed transverse and the adjustable transverse links are of hard construction which give precise handling and minimizes transient steer effects. The soft bush allows for small amounts of toe-in during cornering.