Land Rover Discovery: Lower Control Arm

1. Nut - Rear attachment (2 off)
2. Bush
3. Ball joint
4. Bolt - Rear attachment (2 off)
5. Bolt - Air duct - Brake cooling attachment (if fitted)
6. Air duct - Brake cooling (if fitted)
7. Subframe
8. Bolt - Front attachment
9. Height sensor mounting
10. Bush

The lower control arm assembly consists of a pressed steel lower control arm, two bushes and a ball joint.

The ball joint attaches the outer end of the lower control arm to the wheel knuckle. A nut and bolt clamp the ball joint stud to the wheel knuckle.

Two inner attachments locate the inner end of the lower control arm in the subframe. The forward attachment is a non-serviceable rubber bush which is pressed into the lower control arm. This joint locates in a slot in the subframe and is secured with a bolt which is screwed into a threaded boss on the subframe.

The rearward attachment is a bush which is located on a spigot on the lower control arm. The bush outer metal has a bracket assembly welded onto it which provides for its attachment to the subframe with two bolts and nuts.

The bush contains hydraulic fluid and valves which allow controlled displacement of the bush to improve bump and handling characteristics and also reduce road noise transmission. The bush becomes progressively stiffer as the force on it increases, such as severe braking.

The Air duct - Brake cooling is mounted below the lower control arm to deflect cooling air towards the brake system. The Air duct - Brake cooling is flexible to reduce damage when travelling over uneven ground.

NOTE:

The Air duct - Brake cooling is only fitted on vehicles with 18 inch front brakes.

WHEEL KNUCKLE AND HUB

1. Clamp bolt
2. Locknut
3. Wheel knuckle
4. Anti-lock Brake System (ABS) wheel speed sensor mounting
5. Steering tie-rod attachment
6. Locknut
7. Wheel stud (5 off)
8. Wheel hub
9. Circlip
10. Wheel bearing
11. Disc shield attachment (3 off)
12. Brake caliper attachment (2 off)
13. Clamp bolt
14. Air duct - Brake cooling - Caliper (if fitted)
15. Bolt - Air duct - Brake cooling - Caliper attachment (2 off) (if fitted)

The cast aluminum wheel knuckle provides the attachment for the lower control arm, spring and shock absorber assembly, wheel hub, bearing assembly and the steering tie-rod.

The extended lower boss on the wheel knuckle provides for the attachment of the steering gear tie-rod ball joint.

The upper section of the wheel knuckle has a location hole for the shock absorber body. The shock absorber body slides into the hole and locates against an abutment. The rear face of the hole is split and allows the shock absorber body to be clamped in the wheel knuckle with a nut and bolt.

Mounting locations are provided for the brake caliper, the brake disc shield and the Air duct - Brake cooling - Caliper. A hole in the top face of the wheel knuckle provides the location for the Anti-lock Brake System (ABS) wheel speed sensor, which is secured with a bolt.

The wheel hub is located in the wheel bearing, which is installed in the wheel knuckle and secured with a circlip. The inner face of the wheel bearing incorporates a pulse ring for the ABS wheel speed sensor.

NOTE:

The Air duct - Brake cooling - Caliper is only fitted on vehicles with 18 inch front brakes

STABILIZER BAR

1. Locknut (hidden) (2 off)
2. Ball joint
3. Stabilizer bar link
4. Ball joint
5. Locknut (2 off)
6. Stabilizer bar
7. Bush (2 off)
8. Nut (4 off)
9. Clamp (2 off)
10. Collar
11. Bolt (4 off)

The stabilizer bar is attached to the rear of the subframe with bushes and mounting brackets. The pressed steel brackets locate over the bushes and are attached to the cross member with nuts and bolts. The stabilizer bar has 'anti-shuffle' collars crimped in position on the inside edges of the bushes.

The collars prevent sideways movement of the stabilizer bar.

Each end of the stabilizer bar curves forwards to attach to a ball joint on a stabilizer bar link. Each stabilizer bar link is secured to a bracket on the shock absorber body with a locknut. The stabilizer bar links, which are not handed, allow the stabilizer bar to move with the wheel travel.

The stabilizer bar bushes are the compression type which grip the bar under compression by the mounting brackets. When fitting replacement bushes, it is important to make sure that the bushes have the correct color code and are correctly orientated to the stabilizer bar. Failure to correctly align the bushes will result in excessive pre-load (wind-up) in the bushes when the suspension is at its nominal ride height.

Spring and Shock AbsorberRear Suspension Lower ARM (G1774719) / Removal and Installation

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