Before undertaking any work, technicians are strongly advised to wear protective glasses, gloves and ear protection – the pressure in an air suspension system can be up to 18 bar.
The pressure should be released and the power supply to the compressor disconnected before disassembling the air hoses and components.
If a vehicle drops more than 2.5cm overnight, there is a leak in the system.
Leak detection often only requires a water and soap spray – bubble will indicate the leak.
If the car is lower in one corner, or the car is not levelled, this can also be cause by a defective valve block.
A burned out compressor can be confirmed by smell, and/or the color of the metal body.
Brown- colored labels on the compressor unit are also easy-to-see indicators.
Depressurising the system
Depressurising the system can be done either at the compressor or the air bellow side.
Never fully remove the air fitting at once, but slowly remove to relieve the pressure.
Depending on the vehicle’s make and model, a diagnostic tool is needed to activate the solenoids to depressurize the air bellows.
You can recognise this by the presence of a connector on the air spring.
Check if the vehicle features a special jack mode.
If present, use it to prevent the air being released from the bellow when jacking up the car.
If not present, the car can be jacked without any precautionary measures.
Some systems automatically recognise that the car is jacked and retain the desired amount of pressure in the air springs.
Never fully lower the car with the lifting device when the air suspension system is depressurised.
The air spring could unfold incorrectly and the crimp ring can dislodge.
Besides, an aging compressor might not be able to produce enough pressure to raise the car from zero.
The relay could get damaged, or in worst case the compressor could burn out in its attempt to pressurize the system to the operational level.
The air springs should be mounted the way they came out of the box.
Do not stretch them or pre-pressurize them to make the installation easier.
During inflation it could fold out incorrectly and get damaged.
VOSS connectors usually do not need tightening.
Ignoring this might damage the thread which can cause air leakage.
Respect the manufacturers torque specifications at all times.
Find cause of failure
Always replace the relay when mounting a new compressor.
It is likely that the old relay has become “sticky”, causing the new compressor to continuously operate.
This will eventually lead to a burned out compressor.
Remind yourself that a compressor is usually not the actual cause of a non-functioning air suspension system, but rather the consequence of a large leakage in another part of the system.
Therefore, making the correct diagnosis is crucial.
Check all lines, connections and air springs for leaks after the compressor is working again.
Struts and shocks
Critically inspect the air suspension strut or shock absorber for function and oil leakage when replacing a leaking air spring.
Oil deteriorates the rubber of the air bellows and drastically lowers the lifespan of the part. Secondly, if the shock absorber is no longer performing its task properly, the air spring overworks and will get damaged quickly.
Diagnostic tools and software updates
After the test drive, make sure no fault codes are re-entered in the system.
It is recommended that you check the height sensor parameters with a diagnostic tool and adjust if necessary.
This ensures the correct height at each corner of the vehicle enabling the system to respond correctly to inputs when driving. Additionally, perform a wheel alignment when the shock absorber or strut is replaced.
Always perform a dealer software update if this is required in the installation manual.
Ignoring this will cause the compressor to not work as it should possibly leading to a mal-functioning or burned compressor.
With more than 30 years of experience in engineering, designing and manufacturing high quality air suspension components for the aftermarket, Arnott is the technical expert when it comes to air suspension systems.
Arnott’s products are produced with high-quality, OE components offering exact form, fit and function.
For further information about Arnott, select ‘more details’ below.