The front and rear breathers are set up differently. From memory, here,
they are both a 10x1.25mm thread, which is close enough to a 1/8" NPT thread
for all practical purposes. Only use brass fittings in the axles! You
want the fittings to give way to the axle threads, not vice versa. If you
use cast iron fittings, you're really asking for grief (unless you run a die
over them to rethread them to 10x1.25mm).
Anyway, on the front, it's easy. Unscrew the old breather, then screw in a
reduction fitting (1/4" NPT male to 1/8" NPT male) then screw in a 1/4" NPT
barbed fitting that you can attach a hose to.
The rear is a bit more difficult. Assuming that your '72 is the same as the
'77 and '81 that I relocated, you will find the breather running through the
'Y' block for the brake lines. Unscrew the old breather, then get a 1 1/2"
1/8" NPT nipple (just a short chunk of pipe with 1/8" NPT male threads on
each end) and screw a 1/8 to 1/4NPT bushing onto one end so that the nipple
looks like a bolt. Now screw that in where the breather was. This will
hold the 'Y' block in place. Screw a female 1/4"NPT barbed fitting onto