landrover Workshop Repair Guides

Land Rover Workshop Service and Repair Manuals

Description - SLS|Page 968 > < Description - SLS|Page 966
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REAR SUSPENSION

64-14

DESCRIPTION AND OPERATION

The compressor is attached with Allen bolts to the motor housing and sealed with an O-ring. Attached to the 
compressor is the air dryer which contains a silicate box for removing moisture from the compressed air. Air supplied 
to inflate the air springs passes through the air dryer. When the air springs are deflated, the exhaust air also passes 
through the air dryer, removing the moisture from the unit and expelling it to atmosphere.

Attached to end of the air dryer unit is the pressure limiting valve. The valve protects the air springs from over inflation. 
The pressure limiting valve also operates when the exhaust valve is opened. The valve is pneumatically operated, 
responding to air pressure applied to it.

The exhaust valve is also located with the pressure limiting valve. The exhaust valve is solenoid operated by the ECU 
and directs air from the air springs and control valves to atmosphere when required.

The two air control valves for the LH and RH air springs are located at the forward end of the housing. Each valve is 
connected to the compressor/air dryer unit through a shared single pipe which directs air to and from the air springs. 
Each control valve is individually operated by the ECU.

All air connections to and from the air supply unit are made through the SLS air harness which is located along the 
left hand chassis longitudinal.

If faults occur with the air supply unit, fault codes are stored in the SLABS ECU. These fault codes cover the 
compressor power supply and the LH and RH air control valves and the exhaust valve. The current and past fault 
codes can be retrieved with TestBook. TestBook can also be used to operate the compressor and the valves for 
diagnostic purposes.

Air intake filter
The air intake filter is located in the left hand 'E' post, behind the tail lamp assembly. The filter comprises a plastic 
moulded housing which contains two filters of differing density to remove particulate matter from the air drawn in by 
the compressor. The air intake filter has a pipe which is connected to the SLS air harness by a quick release 
connector. The air intake filter must be replaced as an assembly.

Air intake/Exhaust silencer
The air intake/exhaust silencer is located on the outside of the left hand chassis longitudinal, behind the air supply 
unit. The silencer is an integral part of the SLS air harness and cannot be serviced individually.

The intake and exhaust air to and from the compressor passes through the silencer. The plastic moulded silencer has 
two chambers. One chamber reduces system exhaust noise and the other dampens intake air pulses produced by 
the compressor.

Description - SLS|Page 968 > < Description - SLS|Page 966