ARB RD40 - Manual (Page 27)

4 Installing the Air System
25
NOTE : To remove the air line from the push-in fitting; while
holding the flange of the fitting out, push the air line
into the fitting as far as possible, then press the flange
inward, then pull the air line free of the fitting.
4.3 Connection to the Bulkhead Fitting
Trim the air line to length using a sharp knife.
Insert the support spring over the end of the air line - small end first.
(Fig.16.)
Insert the outer compression nut over the air line.
Insert the 5mm [0.197”] ferrule over the end of the air line. Leave
approx. 5mm of tubing between the ferrule and the end of the tube.
Figure 16.
Insert the support tube all the way into the end of the air line.