Safety Checks - Suspension
Most modern coaches and buses have an air suspension system. This could be electronically controlled or have a basic
levelling-valve set up.
In either case, the correct ride height setting is essential as it affects passenger comfort and fuel economy. An incorrect
setting could also result in premature failure of various
components, including the tyres.
As with any air controlled system the quality of the air supply should be maintained to prevent premature failure of air valves in the suspension.
Shock absorbers are a vital component in the suspension system; their ability to adequately control the compression and rebound movements of the suspension will be reduced if they are defective, leaking or adjusted incorrectly.
A significant sign of a failed shock absorber would be the difference in the ride experience. A bumpy ride or hard ride could be a warning that the shock absorber has been adjusted incorrectly.
In the event of a leaking shock absorber, it would be advisable to change the sets in pairs. Air bags are a crucial part of the suspension system and can cause serious damage if not
Signs of wear and age on the air bellow assembly could be cracking or splitting of the rubber. This can weaken the part and lead to leaking air, or in some cases complete failure.
The pedestal of the air bellow and the top plate are equally
important. Corrosion and dirt ingress are both things to look out for,as they will act as an abrasive. If the chassis is being repainted it is recommended to cover the air bag assembly, as it can be susceptible to some chemicals.
Height sensors and levelling valves are items that control the
height of the air bellows.These items are moving parts; therefore some wear is expected over time. However, without consistent
monitoring of any damage, suspension can become erratic
or suddenly raise or lower