TM 9-2330-238-14
4-44. RELAY VALVE MAINTENANCE (Con’t).
5.
6.
Close shut-off valve in emergency line on towing
vehicle and disconnect EMERGENCY air cou-
pling (1), Apply soap and water solution to
exhaust port (8) and check for leakage.
If leakage is detected, replace relay valve (4).
c.
REMOVAL
1.
Uncouple semitrailer from towing vehicle (para 2-11).
2.
Open draincock on air reservoir and release air pressure.
3.
Disconnect and tag service and emergency air tubes (6 and 10), air reservoir air tube (11) and airbrake chamber
air tubes (9) from relay valve (4).
4.
Remove two capscrews (12), Iockwasher, and relay valve (4) from mounting bracket (2). Discard Iockwasher.
5.
If replacing relay valve (4), remove fittings (5) from old relay valve.
1.
If replacing relay valve (4), install fittings (5) in new relay valve with antiseizing tape.
2.
Position relay valve (4) in place on mounting bracket (2) and install two capscrews (12) and new Iockwasher.
3.
Connect airbrake chamber air tubes (9), air reservoir air tube (11) and service and emergency air tubes (6 and
10) to relay valve (4). Remove tags.
4.
Close draincock on air reservoir.
TA701991
4-91
