3 installing the air locker, Bench testing the air locker – ARB RD138 User Manual
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3 Installing the Air Locker
22
3.9
Bench Testing the Air Locker
c To test the Air Locker, when 620kPa [90 PSI] shop air is applied to
the seal housing tube, the Air Locker should engage.
c Check all fittings and the seal housing for air leaks. 
c Rotate the differential carrier by turning the pinion flange whilst 
applying air pressure.
NOTE : An accurate way to test for air leaks is to fit a shut-off
valve to an air pressure gauge (Available as ARB part 
#ALTG01). Charge with shop air until 620 KPA [90 PSI] 
is reached, shut the valve off, disconnect the air hose, 
and watch to see if there is any drop in pressure. Any 
gradual pressure drop indicates an air leak. (Fig.19.) 
Figure 19.
 
 
 
 
 
 
 
 
 
 
 
c If a leak is found to be present, spray a soap and water mixture
onto the bulkhead air fitting. Bubbles should appear at any leak 
points. 
NOTE : Do not spray this soapy mixture inside the differential.
c Check that leaky fittings have been adequately tightened. 
c Disassemble, clean threads, and reapply thread sealant if leaking 
persists.
c If a leak is found at the seal housing, carefully remove and refit. Be
very careful with the O-rings and check they have not been 
damaged during installation. 
