ARB RD158 - Manual (Page 18)

4 Installing the Air Locker
16
4.5 Calculation & Selection of Pre-Load Shims
In order to pre-load the tapered roller bearings in your Air Locker,
measurements need to be taken so that a value can be calculated for
the shim thickness ‘E’ in Figure 9.
 Hold the shim pack, master shim and tapered roller bearing cup in
place on the case side.
 Hold the seal housing, master shim and bearing cup on the ring
gear side. Then insert the Air Locker assembly into the differential
housing with the seal housing tube pointing straight out of the
housing.
 Install bearing cap on the case side, and finger tighten the bolts.
 Push the Air Locker hard across to the case side, and measure the
gap (end float) between the seal housing and the differential
housing with a feeler gauge.
NOTE : This ‘end float’ measurement determines the shim
thickness necessary to achieve ‘neutral pre-load’.
Adding more shim than this measurement becomes
the actual ‘pre-load’.
 Consult your vehicle manufacturer’s service manual to determine
the carrier bearing pre-load amount specified for your vehicle.
 Add the specified pre-load amount to the measurement taken with
the feeler gauge to determine a shim amount for ‘E’ in Figure 9.
PRE-LOAD + END FLOAT = SHIM PACK
 Select suitable shims from the supplied shim kit to make up a shim
pack of this thickness and leave it aside for final assembly.
 Remove the Air Locker and assemble the shim pack onto the seal
housing spigot (Figure 9.).
 If applicable, spread the differential housing again (Refer Sect 2.6).
NOTE : If the carrier is too difficult to install with the added
shim pack then the spreader tension may need to be
increased. Do not spread the housing more than
0.50mm [0.020”].
 Reinstall the Air Locker as before (i.e., with only one bearing cap).
 Release all spreader tension.