General information (Opel Astra H)

Note: The suspension of the Estate and Zafira models is similar in design to that used on the Hatchback models. The difference between the models is the wheelbase, which is 75 mm longer on the Estate models and 89 mm longer on the Zafira models than on the Hatchback models.

Attention: When assembling suspension and steering components, it is imperative to comply with the tightening force requirements for threaded connections (see Specifications)! If you do not have the necessary experience, repair work should be carried out at a service station.

1. The design of the independent front suspension with a subframe and lower control arms, MacPherson struts and an anti-roll bar is shown in the accompanying illustration. The supporting element of the front suspension is a closed subframe, which is attached to the body at 6 points through shock-absorbing bushings. Additionally, 2 side supports are connected to the bottom of the body at the rear. The struts consist of telescopic shock absorbers and coil springs and are attached with their upper ends to reinforced supports on the mudguards of the front wings, and with their lower ends to the steering knuckle assemblies. The hub with the wheel bearing is made in the form of a single compact unit, non-adjustable bearings do not require maintenance. The hub assembly is installed in the steering knuckle. The lower parts of the steering knuckles are connected to the lower suspension arms by means of ball joints. The inner ends of the arms are attached to the subframe by means of rubber-metal silent blocks, limiting the lateral and longitudinal movement of the front wheels. The anti-roll bar is standard on all models. The anti-roll bar is mounted on the subframe and connected to the suspension struts by two struts, which can be plastic or steel depending on the model. It is designed to compensate for the lateral roll of the car when cornering. The front suspension does not require maintenance during operation.





2. The rear torsion bar suspension consists of 2 longitudinal arms welded to a U-shaped cross beam (see accompanying illustration). The rear ends of the suspension arms are equipped with mounting seats and sockets for fastening the spring assemblies and shock absorbers, as well as vertical flanges to which the rear wheel hub assemblies are bolted together with the brake shields. The front ends of the arms are equipped with silent blocks. Bolts are threaded through the silent blocks, fixing the suspension arms in brackets bolted to the body side members. The upper ends of the shock absorbers are attached to the supporting elements of the body bottom. The springs are installed separately from the shock absorbers (which increases the space of the cargo compartment) and are secured by two saddles, one of which is attached to a flange on the lever, the other to the bottom of the car. The wheel bearings are built into non-separable hub assemblies. Station wagon models can be equipped with a rear ride height adjustment system (see Chapter "Controls and operating techniques").



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3. The main elements of the steering system are the steering wheel with the steering column, the steering gear with the toothed rack and the steering rods (see accompanying illustration). The column is connected to the mechanism by means of an intermediate shaft equipped with crosspieces. The sliding upper section of the steering column is equipped with a lock that blocks the steering gear. The steering column transmits the control movement to the steering gear via a toothed engagement with the rack. The steering gear is mounted on the front suspension subframe. The steering rods are attached to the steering knuckle arms using tips. The steering gear must not have any play and, accordingly, has no adjustment indicators. If the dust boots are damaged or play appears as a result of wear of the steering rod tips, the corresponding elements must be replaced. All models are equipped with an electro-hydraulic steering drive system as standard. The electric steering pump is maintenance-free. The hydraulic fluid reservoir is built into the pump assembly. The pump sucks oil from the reservoir and delivers it under high pressure to the steering gear, where it is Depending on the direction of rotation, it enters the corresponding cavity of the working cylinder and exerts pressure on the piston of the toothed rack and thus ensures the rotation of the wheels.

Note: Depending on the engine model, the electric power steering can be manufactured by two different manufacturers. The TRW power steering has a cylindrical reservoir and non-detachable contacts for the oil pump wiring. The ZF power steering reservoir is made in the form of a truncated cylinder with two flat side faces.

4. Often, when replacing suspension components, you have to deal with fasteners that are difficult to loosen. The fasteners "stick" because they are constantly exposed to external influences, are in contact with water, dirt, soot and other substances that promote corrosion. In order to facilitate the procedure of loosening such "stuck" fasteners, they should be soaked in plenty of penetrating oil or a special rust-corroding agent in advance. Cleaning the exposed threaded parts of the fasteners with a stiff wire brush also helps to loosen rusted nuts. In particularly difficult cases, you can use a chisel/punch and a heavy hammer to loosen a "stuck" bolt/nut. Make sure that the chisel/punch does not come off, try not to damage the threads with imprecise blows. Another quite effective method is to heat the fastener that is difficult to loosen and the surrounding component surface with a blowtorch or gas torch, although the authors of this Guide do not recommend resorting to this technology unless absolutely necessary due to its potential danger associated with the possibility of fire and the risk of burns. Various types of extensions, collars and pipe attachments are designed to increase the torque when loosening the fastener. Sometimes a nut/bolt begins to give in after it has been slightly tightened clockwise. All fasteners, the loosening of which required the use of extraordinary measures during assembly, are subject to replacement!

Note: After delivery, carefully check the condition of the fasteners and, if necessary, replace them with elements of the same size.

Warning: Do not attempt to straighten deformed suspension and steering components under any circumstances - replace defective parts with new ones!

5. Since suspension component maintenance procedures are performed under the vehicle, care should be taken in advance to ensure that the vehicle can be lifted and secured in the raised position (prepare a reliable jack and supports).

Caution: Never carry out any work under a vehicle that is secured in a raised position only by means of a jack!

6. Optimal running characteristics and minimal tire wear are achieved provided that the wheel alignment angles are adjusted correctly. In case of uneven tire wear, as well as unsatisfactory road stability, it is necessary to contact a service station to check the suspension geometry and wheel alignment. The check is carried out only with the help of special equipment.

Precautionary measures

See also Chapter "Controls and operating techniques".

7. The steering wheel has an airbag built into the hub. To ensure that the airbag operates properly in an emergency, and to avoid the risk of injury from accidental activation, certain precautions must be taken (see also Chapter 12):

• a) Before starting work on the airbag or near the SRS wiring locations, be sure to disconnect the negative battery cable. Work should be started at least one minute after disconnecting the battery - time is needed to discharge the backup power source capacitor;
• b) Do not allow the airbag module to heat up to over 90°C. Do not turn the removed airbag module upside down;
• c) Avoid contact of the module surface with solvents and detergents - use only a clean, slightly damp cloth to wipe the steering wheel;
• d) The SRS control unit and airbag modules are sensitive to directional overloads (impacts) and must be replaced after a fall from a height of more than 50 cm;
• e) Before carrying out welding work on the vehicle, be sure to disconnect the SRS control unit wiring;
• f) On models equipped with passenger air bags, to avoid injury, do not install any additional equipment or place any foreign objects in the air bag deployment area.