ARB RD131 - Manual (Page 15)

4 Installing the Air Locker
Lubricate the seal housing running surface on the Air Locker carrier
with oil. Assemble the bearing cup onto the left-hand side of the Air
Locker.
NOTE : No shims should be assembled onto the seal housing
at this time. The bearing cup should sit directly
against the seal housing.
Carefully install the seal housing by sliding it all of the way onto the
bearing journal with a gentle twisting motion. This will allow the O-
rings to engage gently.
4.4 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 5.
Hold the bearing cup and shim pack ‘D’ (Fig.4.) in place, and insert
the Air Locker into the housing.
Push the Air Locker hard across against the bearing and shim pack
‘D’, and measure the gap between the end of the seal housing
assembly and the bearing seat of 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 5.
PRE-LOAD + END FLOAT = SHIM PACK
Select suitable shims from the shim kit supplied with your Air
Locker to make up a shim pack of this thickness. (Refer to section
3.2 for methods of shim adjustment).
The seal housing will have to be removed in order to add shim pack
‘E’. Ensure that the seal housing is re-installed correctly.
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