Checking shock absorber

GENERAL INFORMATION

The following symptoms indicate a faulty shock absorber:

– Additional body movement when driving over uneven road surfaces. – Increasing body oscillation amplitude over successive bumps. – Wheel hop when driving on a normal road. – Involuntary turning of the vehicle during braking. This may be caused by other factors. – Instability in corners due to poor road grip. – Increased tire wear with cupped tread edges. – A rattling noise may also indicate defective shock absorbers. This noise may also be caused by other factors, such as loose bolts and nuts, or failed wheel bearings and constant velocity joints. Therefore, always check the condition of the shock absorbers before replacing them.

The shock absorber can be checked manually. However, an accurate check of shock absorber operation is only possible with a shock absorber tester or a special test machine.

Manual check

PROCEDURE

1. Remove the shock absorber.

2. Hold the shock absorber in its working position, extend and compress it. Throughout the entire stroke, the shock absorber must move smoothly and evenly.

3. On gas-charged shock absorbers, the rod returns to its initial position on its own if gas pressure is sufficient. If the rod does not return, this does not necessarily mean the shock absorber must be replaced. Its operating principle corresponds to that of a conventional shock absorber as long as there is no significant oil leakage. The damping action of the shock absorber is also retained without gas pressure. However, its noise characteristics deteriorate.

4. If the shock absorber is operating normally, minor traces of leaked oil are not a reason for replacement. The main rule is: if oil is visible coming from the rod seal but does not spread beyond the lower spring seat, the shock absorber is serviceable. Minor oil leakage is even somewhat beneficial, as it lubricates the seal and extends its service life.

5. If there are significant oil leaks, the shock absorber must be replaced.