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Rear Suspension





Rear Suspension

REAR SUSPENSION

Rear Suspension Components









The independent rear suspension arms have been designed for maximum ground clearance. Wheel alignment can be adjusted for camber and toe-in using eccentric bolts.
The following wheel travels are shown for on road and off-road vehicle operation. The difference between the two operating conditions is a result of operation of the rear cross-link valve. When the cross-link valve is opened the suspension travel is as given for off-road wheel travel. When the cross-link valve is closed the suspension travel given for on road applies.
The off road mode wheel travel is:
- 190 mm bump
- 140 mm rebound
- This gives a total of 330 mm off road suspension travel.
The on road standard height wheel travel is:
- 140 mm bump
- 190 mm rebound
- This gives a total of 330 mm on road suspension travel.

NOTE:
Overall wheel travel stated above will still be achieved when both wheels are moving in parallel together.
The rear suspension comprises:
- Two dampers
- Two air springs
- Subframe
- Two upper wishbones
- Two lower wishbones
- Two toe control arms
- Stabilizer bar
- Two stabilizer bar links
- Two hub assemblies.

Dampers
The rear dampers are unique to Range Rover and are of a mono-tube design manufactured by Bilstein. The mono-tube design gives the following advantages over conventional twin tube dampers:
- Lightweight construction
- Excellent high frequency response
- Consistent performance - mono-tube design eliminates fluid aeration and emulsification
- Larger diameter piston produces increased fluid displacement for a given damper stroke resulting in more accurate damping control.
The damper comprises a single tube which forms the operating cylinder. The lower end of the cylinder has an eye which accepts the bush for mounting to the lower wishbone. A piston and rod slides inside the cylinder. The rod emerges from the top of the cylinder which is fitted with a rod guide and a seal.
A dust cover is fitted to the top of the piston rod and protects the rod from damage. A bump stop is fitted to the top of the piston rod, under the dust cover, and protects the damper from full travel impacts. A top mount is attached to the top of the piston rod and is secured with a flanged nut. A hardened washer is fitted between the shoulder on the piston rod and the bump washer which is fitted inside the dust cover. When the damper is removed and replaced, care must taken to ensure that the correct hardened washer is refitted in the correct position. The washer prevents the piston rod shoulder causing damage to the bump washer.
The piston is fitted with reed valves which cover a series of holes, through which oil can pass. A chamber at the base of the damper is sealed by a free floating piston. The chamber is filled with inert gas. When the damper is assembled and filled with oil, the gas is in a compressed condition below the piston. On the bump stroke, the downward movement of the piston displaces oil from the full area (bottom) of the cylinder to the cylinder annulus (top). The energy required to pump the oil through the piston drillings and reed valves creates the damping action.
As the piston moves downwards, the volume available on the annulus side of the piston is less than required by the displaced oil from the full area side. When this occurs, the free floating piston moves downwards, further compressing the gas and providing the additional volume for the displaced oil and further enhancing the damping process.
The dampers are located between the lower wishbone and the vehicle body. The lower mounting is fitted with a bush which provides for the attachment to the wishbone with a bolt and nut. The damper top mounting is located in a turret in the body and secured to the body with three nuts. A paper gasket is located between the damper top mounting and the body and prevents the ingress of dirt and moisture into the mounting studs and corresponding holes in the body. It is important that this gasket is discarded and replaced with a new item when the damper is removed.

NOTE:
The dampers fitted to TDV8 vehicles differ to the dampers fitted to petrol vehicles to compensate for the extra weight and handling characteristics of the vehicle.


Air Springs
Each air spring comprises a top plate assembly, an air bag and a base piston. The air bag is attached to the top plate and the piston with a crimped ring. The air bag is made from a flexible rubber material which allows the bag to expand with air pressure and deform under load. The top plate assembly comprises the plastic top plate with a spigot which protrudes through a hole in the subframe. On the side of the top cap is a connector which allows for the attachment of the air hose from the cross-link valve. The piston is made from plastic and is shaped to allow the air bag to roll over its outer diameter. The base of the piston has a splined stud in the center and an offset timing peg for correct orientation of the air spring into the lower wishbone.
The air springs are located rearward of the dampers and are retained between the subframe and the lower wishbone. The air spring is attached to the lower wishbone with a screw which is fitted from the underside of the wishbone into the splined stud on the base of the piston. The air spring top plate is attached to the subframe via an integral 'D' shaped spigot which is secured with a retaining clip.

NOTE:
The air spring fitted to TDV8 vehicles differs to the air spring fitted to petrol vehicles to compensate for the extra weight of and handling characteristics the vehicle.


Subframe
The subframe is fabricated from steel tubing to provide a robust platform for the mounting of the suspension and the rear differential. The subframe is attached to the vehicle body via four, voided rubber mounts.
Two bushes at the front of the subframe and one at the rear allow for the attachment of the rear differential. Additional brackets, bolted to the subframe, allow for the attachment of the height sensors. The stabilizer bar is attached across the rear of the subframe and is mounted in flexible bushes which are secured with 'D' shaped clamps.

Upper and Lower Wishbones
Upper Wishbone
The steel fabricated upper wishbone has two bushes pressed into housings which provide for the attachment to the subframe. The bushes are located between brackets on the subframe and are secured with bolts and nuts. The outer end of the upper wishbone has two brackets with slotted holes. A boss on the hub is fitted with a ball joint which locates between the brackets and is secured with an eccentric bolt, washer and nut. This allows for the adjustment of the rear wheel camber. Rotation of the bolt moves the eccentric head against a recessed slot in the bracket, moving the location of the hub in the upper wishbone slots, allowing the camber to be adjusted to within the set limits. A rubber bump stop is fitted centrally on the upper wishbone to cushion the wishbone movement when the suspension is at the extremes of its travel.
Lower Wishbone
The lower wishbone is larger than the upper wishbone and is a steel fabrication. Two bushes are pressed into the wishbone and provide for the attachment to the subframe. The bushes are located between brackets on the subframe and secured with bolts and nuts. The lower wishbone has a platform which provides for the attachment of the air spring. A welded bracket allows for the attachment of the anti-roll bar link. A boss on the hub is fitted with a ball joint which locates between brackets on the lower wishbone. The hub is secured to the lower wishbone with a bolt and nut. A bracket with a tubular extension provides for the attachment of the damper lower mounting.

Toe Control Arms
The toe control arm is a forged steel component. One end is fitted with a taper ball joint and the opposite end has a bush pressed into an integral housing.
The bush locates between brackets on the subframe and is secured with a special eccentric bolt, washer and nut. This allows for the adjustment of the rear wheel toe-in. Rotation of the bolt moves the eccentric head within a recessed slot in the bracket, allowing the toe-in to be adjusted within the set limits.
The taper ball joint locates in a tapered hole in the hub and is secured with a nut.

Stabilizer Bar and Links
The stabilizer bar is fabricated from 26.5 mm diameter, solid spring steel. The stabilizer bar operates, via a pair of links, from a bracket on the upper face of each lower arm.
The stabilizer bar is attached to the rear of the subframe with two bushes which are bonded to the bar and cannot be removed. Clamp plates are pressed onto the bushes and must not be removed. The stabilizer bar is secured to the subframe with the clamp plates which are secured with bolts.
The ends of the stabilizer bar are attached to the lower arms via stabilizer bar links.
Each stabilizer bar link has a ball joint fitting mounted at 90° to the axis of the link at each end which improves response and efficiency. The top ball joint attaches to the stabilizer bar and is secured with a nut. The lower ball joint attaches to the lower wishbone and is secured with a nut. The ball joints on the stabilizer bar links are not serviceable and if replacement of either is necessary, a new stabilizer bar link will be required.
A hardened steel washer is fitted between the lower ball joint and the bracket on the lower wishbone. The hardened washer prevents the ball joint damaging the bracket which could lead to loosening of the nut torque. When the link is removed it is important to ensure that the correct hardened washer is replaced in the correct position.

Hub Assembly
The hub assembly comprises a wheel hub, drive flange and bearing. A seal and bearing are fitted in the wheel hub and are secured with a circlip. The drive flange has wheel studs attached to it and locates on the splined drive shaft and is secured with a stake nut.
The cast wheel hub has a vertical boss with a cross hole. A ball joint is pressed in the hole and provides the attachment point for the upper wishbone. The upper wishbone is secured to the wheel hub with a bolt and nut. An additional boss with two cross holes provide location for the brake caliper.
A second vertical boss with a cross hole at the bottom of the wheel hub provides for the attachment of the lower wishbone. A ball joint is pressed in the hole and the lower wishbone is secured with a bolt and nut. A further tapered hole in the wheel hub allows for the attachment of the toe control arm ball joint.
A hole is machined in the wheel hub at 90° to the hub bearing. This hole allows for the fitment of the ABS (anti-lock brake system) wheel speed sensor which is secured with a screw into an adjacent threaded hole. The speed sensor reads off a target which is part of the drive shaft assembly.

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