Suspension System: Procedures

Suspension System:

Checking shock absorbers

Part 1. Preparation and safety

Objective

• Check the serviceability of the shock absorbers and struts.

Personal safety
Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:

Suspension System: Suspension system layouts

Suspension System:

Driven rear suspension layouts

A number of different layouts are used in ”driven” or 'live' axle rear suspension systems.

This driven or 'live' rear axle arrangement consists of: shock absorbers; u-bolts; fixed shackle; rebound clips and swinging shackles.

Suspension System: Rear suspension types & components

Suspension System:

Rigid axle leaf spring suspension

The front of the leaf spring is attached to the chassis at the rigid spring hanger. This spring eye is bushed with either rubber bushes or, in the case of heavy vehicles, steel bushes.
The axle housing is rigid between each road wheel. This means that any deflection to one side is transmitted to the other side.

Suspension System: Front suspension types & components

Suspension System: 

Strut suspension

The shock absorber is contained inside the strut, and is a direct acting telescopic type shock absorber. The coil spring is mounted over the strut, inside the suspension tower.
The strut has an upper mounting point in the suspension tower.
For the front steerable suspension, the strut’s upper mounting is bushed, or bearing-mounted, to allow for the steering movement.

Suspension System: Shock absorber types

 Suspension System:

Hydraulic shock absorbers

The most widely-used hydraulic shock absorber is the direct-acting telescopic type. It can be fitted as a self-contained unit, or combined with a suspension strut. The strut type uses the same principle of operation but it is considerably larger.
The hydraulic shock absorber provides its dampening action by transferring oil, under pressure, through valves which restrict the oil flow.
The twin-tube type is the most common. The outer tube is normally attached to the suspension member at its base, and the inner tube provides a working cylinder for a piston which is attached to a piston rod. The piston rod is connected to the frame at its outer end, and a bearing at the top of the outer tube keeps the rod in alignment as it moves in and out of the shock absorber, with suspension action.
A seal above the bearing prevents oil leakage, and keeps out dirt and moisture. A shroud protects the rod from damage.

Suspension System: Type of Suspension Springs

 Suspension System:

Coil springs

Coil springs are used on the front suspension of most modern light vehicles, and in many cases, they have replaced leaf springs in the rear suspension.
A coil spring is made from a single length of special wire, which is heated and wound on a former, to produce the required shape.
The load-carrying ability of the spring depends on the diameter of the wire, the overall diameter of the spring, its shape, and the spacing of the coils.

Suspension System: Type of suspension

 Suspension System:

Suspension systems

The purpose of the complete suspension system is to isolate the vehicle body from road shocks and vibrations which would otherwise be transferred to the passengers and load.
It must also keep the tires in contact with the road, regardless of road surface.
A basic suspension system consists of springs, axles, shock absorbers, arms, rods, and ball joints.
The spring is the flexible component of the suspension. Basic types are leaf springs, coil springs, and torsion bars.

Suspension System: Principles of suspension

 Suspension System:

 Principles of suspension

The suspension system isolates the body from road shocks and vibrations which would otherwise be transferred to the passengers and load.
It also must keep the tires in contact with the road. When a tire hits an obstruction, there is a reaction force. The size of this reaction force depends on the unsprung mass at each wheel assembly.
The sprung mass is that part of the vehicle supported by the springs - such as the body, the frame, the engine, and associated parts.