ARB RD125 - Manual (Page 13)

3 Installing the Air Locker
11
c If no drainage slot is present at the upper left-hand side (refer to
Fig.4.) of the housing at all, then a slot (not a hole) will have to be
created as clearance for the seal housing tube (Refer to Section 3.8
Reinstalling the Bearing Caps).
c If drainage exists but is inadequate then a slot or hole should be cut
into the housing on the lower side of the tube(s) to allow oil out of
the axle tube area.
NOTE : Figure 7. shows upper and lower drainage slots cut
into a bearing seat which had no existing drainage at
all before modification.
Figure 7.
c Remove any sharp edges left behind by the modifications that
could break off and fall into the cavity.
c Make sure any grinding dust, filings or drill chips left behind by
cutting the drainage slots are completely cleaned out of the
housing.
c Check that the axle air vents are clear and working correctly.