ARB RD82 - Manual (Page 14)

3 Approximate Backlash Shimming
12
3.2 Calculation and Selection of Pre-Load Shims
Ideally, the measurement you recorded as ‘C’ from the Air Locker
differential will closely match ‘A’ on the existing differential (within
0.1mm [0.004”] ) and then the factory shim can be reused, however,
quite often these measurements will vary slightly between one factory
differential and the next.
If this is the case you must create a new shim pack thickness by using
the measurements you recorded earlier to find a desired measurement
for ‘D’ in Figure 6.
Use the following calculation:
A + B – C = D ( Replacement Shim Pack )
HINT : If your calculations are correct then the following
equation will also be true:
A + B – C – D = ZERO
To achieve the desired shim thickness you can:
• Machine down the factory shim thickness.
• Add shims between the factory shim and the bearing cup.
• Purchase new factory shims at the desired thickness.
• Use a universal shim kit available from most drive train specialists.
• Add small amounts of shim between the bearing cone and the
bearing seat.
NOTE : NEVER machine the Air Locker.