ARB RD105 - Manual (Page 24)

3 Installing the Air Locker
22
Figure 16.
NOTE : If the master shim is too tight to fully install then the
spreader tension may need to be increased. Do not
spread the housing more than 0.50mm [0.020”].
c Release all spreader tension.
c Check that some backlash can be felt between the ring and pinion
gears. No backlash would be an early indication of incorrect shim
thickness.