HOW THE ARB AIR LOCKER WORKS


An ARB AIR LOCKER is a unique type of replacement differential center which
allows the driver to choose between a conventional or a fully locked differential by
operating a rocker switch on the dashboard. The ability to manually engage and
disengage means that the ARB AIR LOCKER can be fitted to the front diff, as well as
the rear diff, without affecting the steering when disengaged.


When the ARB AIR LOCKER is engaged the air solenoid valve (located on the
compressor) opens, and compressed air is fed down the plastic feed line to a bulkhead
fitting installed in the differential housing. A steel tube runs from the bulkhead fitting
to an air seal housing which is locked in position on the bearing journal over a small
air inlet hole in the differential. Compressed air is thus injected into the ARB AIR
LOCKER while it is rotating.


The compressed air activates an annular piston built into the differential and
completely-locks the differential via a large locking gear. When the dashboard
mounted switch is turned off, the compressed air is exhausted through the solenoid
valve, and small heavy duty coil springs in the differential release the locking ring.
Now the differential acts as a normal "open" differential.


The compressor kit, when supplied, is located in any convenient position in the engine
compartment or, alternatively, inside the cabin of the vehicle. A pressure switch is
incorporated which turns the compressor off when the tank pressure reaches a preset
maximum, and on if the pressure drops to the preset minimum. The compressor is
connected into the ignition circuit, via an isolating switch (which is supplied in the
compressor kit,) so that it can be actuated when use of the ARB AIR LOCKER is
engaged, or, the pump-up kit is required.


When ARB AIR LOCKERS are installed in both the front and rear differentials a
unique feature in the wiring prevents the front ARB AIR LOCKER from being
engaged unless the rear ARB AIR LOCKER is engaged.