TM 9-2320-272-24-1
Table 2-4. Compressed Air and Brake System Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Test 4. Check primary reservoir air pressure.
Step 1. Stop engine and drain primary air reservoir at drainvalve (6).
Step 2. Remove drainvalve (6) from primary drain line (5).
Step 4. Connect test gauge to primary drain line (5).
Step 5. Direct assistant to start engine and allow air system to build to normal operating
pressure.
Step 6. Check test gauge reading.
a. If test gauge reads normal operating pressure, stop engine, drain air, remove test
gauge, connect drain line (5), and perform test 5.
b. If test gauge reads no pressure, low pressure, or pressure is building slowly, perform
test 6. Remove test gauge and install drainvalve (6) in primary drain line (5).
Test 5. Check primary air system supply line (3) from primary air reservoir to brake pedal valve (1).
Step 1. Stop engine and open remaining drainvalves (7), in sequence shown, until brake system
air pressure is vented.
Step 2. Disconnect primary air system supply line (3) from brake pedal valve fitting (4) and
connect test gauge to supply line (3).
Step 3. Direct assistant to start engine and allow air system to build to normal operating
pressure.
Step 4. Check test gauge reading.
a. If test gauge reads normal operating pressure, replace brake pedal valve (1)
(para. 3-197 or 3-198).
b. If test gauge reads no pressure, low pressure, or pressure is building slowly, repeat
steps 1 and 2, reinstall primary air system supply line (3), and proceed to
test 6.
Test 6. Check one-way check valve (2).
Step 1. Stop engine and open all drainvalves (6) and (7) until brake system air pressure is
vented.
Step 2. Remove one-way check valve (2) (para. 3-186).
Step 3. Inspect check valve (2) for clogging and damage.
a. If clogging or damage is indicated, replace defective one-way check valve (2)
b. If no clogging or damage is present, repair or replace clogged primary air supply
line (3).
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