ARB RD40 - Manual (Page 16)

3 Installing the Air Locker
14
Install the seal housing side bearing cap and hand-tighten the
bearing cap bolts.
NOTE : It is very important to make sure the punch marks
made on the differential housing while removing the
differential are matched to the punch marks on the
bearing cap. The bearing cap must be replaced
exactly as it was removed. (Refer to section 2.4)
Measure to the bearing cap from exactly the same position on the
differential housing that you took the previous measurements from.
(Fig.8.)
Mark the tube position with a center punch where the clearance is
to be made for the seal housing tube.
Figure 8.
Remove the bearing cap from the differential housing.
Measure the distance from the center punch mark made on the
bearing cap to the closest edge of the bearing cap.
If the center punch mark is greater than 6.35mm [¼’’] from the
closest edge of the bearing cap, it is recommended that a small
hole be drilled through the bearing cap (Section 4.7.1). If less than
6.35mm [¼’’] from the edge it is recommended that a notch is filed
into the side of the bearing cap to avoid break-through while drilling
(Section 4.7.2).