TM 5-3825-229-14&P
4-33.
RELAY VALVE (cont)
a.
Removal.
(1)
Tag and disconnect air lines (1) from relay
valve (2).
(2)
Remove tee (3) from relay valve (2).
(3)
Remove relay valve (2) from rear air tank
nipple
(4)
by
turning
entire
valve
counterclockwise.
b.
Installation.
(1)
Install tee (3) on relay valve (2), using
Teflon tape.
(2)
Install relay valve (2) on air tank nipple (4)
and secure by turning clockwise.
(3)
Connect air lines (1) to relay valve (2) and
tee (3) per tagged identification.
(4)
Close drain valves.
(5)
Pressurize air system and test for leaks as
follows.
c.
Testing.
(1)
With brake system fully charged, close
shutoff valve in emergency line on towing
vehicle. Disconnect emergency air hose
coupling. Make sure semitrailer brakes
apply automatically. With relay valve in this
emergency position, coat exhaust port with
soapsuds.
(2)
Leakage tests must not exceed a one-inch
bubble in three seconds. If excess leakage
is found, replace relay valve.
4-69
