ARB RD125 - Manual (Page 26)

3 Installing the Air Locker
24
Figure 17.
NOTE : Excessive tightening of the center compression nut is
not necessary to form a good seal around the tube
and may damage the O-ring, the seal housing tube, or
the threads of the compression nut.
NOTE : Make sure the seal housing tube is all of the way into
the center compression nut while you are tightening
it.