There are many types of suspension fitted to modern cars. The most common type of suspension is the shock absorber combined with a coil spring. The coil springs are fitted to the vehicle under load and no attempt should be made to remove them without specialist equipment.

The coil spring also helps to absorb shocks and holds the car at its correct ride height. The actual shock absorber is in effect a hydraulic piston that constantly exerts a downward pressure forcing the tyre to have constant contact with the road. Without shock absorbers the tyres would constantly bounce off the road surface thus giving no tyre grip and therefore no braking.

The usual cause of Shock Absorber failure is leakage of the hydraulic fluid from its rubber seal. As with all rubber seals, they will perish with age and use. As the fluid level decreases the hydraulic pressure pushing the tyre to the road reduces and the wheel begins to bounce off the road causing reduced grip and braking and increasing uneven tyre wear. If one shock absorber is better than the other then one side of the car will have better grip and braking causing an imbalance, this is why shock absorbers should always be fitted in pairs.

Shock absorbers are checked for leaks on an MOT test but no test
is currently made on their hydraulic effectiveness, at
BEST Autocentres we can test effectiveness using the latest
equipment as well as offering a performance
enhancement using uprated sports shock
absorbers and/or lowering kits.