The relay valve test listed below applies to all
brake relay valves.
RELAY VALVE TEST
(1) Start engine (TM 9-2320-364-10).
(2) Push in trailer charge valve
(3) While assistant fully applies and
releases brake pedal, listen for
pressure to exhaust from relay
(a) If valve air pressure does not
exhaust quickly, perform Steps (4)
and (5) below and replace relay
valve (Para 4-38).
(b) If valve air pressure exhausts
quickly, relay valve is OK.
(4) Pull out trailer charge valve.
(5) Turn OFF ENGINE switch.
This test covers left rear brake chamber, but it
can be used to test operation of all trailer
BRAKE CHAMBER TEST
(1) Cage brake chamber (Para 2-16).
(2) Remove two cotter pins, pins and
rod clevis from slack adjuster.
Discard cotter pins.
(3) Rotate slack adjuster away from
(4) Uncage brake chamber.
(5) Start engine (TM 9-2320-364-10).
(6) Push in trailer charge valve in
truck (Para 2-22).
(7) While assistant fully applies brake
pedal, observe operation of brake
(a) If rod does not move smoothly
into brake chamber, perform
Steps (8) through (10) below and
replace brake chamber
(b) If rod moves into brake chamber
smoothly, brake chamber is OK.
(8) Release brake pedal.
(9) Pull out trailer charge valve in truck.
(10) Turn OFF ENGINE switch.
(11) Cage brake chamber.
(12) Rotate slack adjuster to clevis.
(13) Install rod clevis, two pins, and
cotter pins on slack adjuster.
(14) Uncage brake chamber.