BRAKE CONTROL VALVES INTERNAL LEAKAGE REPAIR AND TEST (AVIM) continued
Table III. Test
Bleed air from valve by first permitting flow
through VALVE port. Cap VALVE port. Hold
pressure 3 MINUTES. Internal leakage
from CYL 2 port is not allowed.
Purge air from valve by applying low
pressure to CYL 2 port. Bleed fluid through
bleeder valve. Close bleeder valve.
Increase and hold pressure 3 MINUTES.
External leakage from CYL 1 port is not
With pressure applied to CYL 2 port and
other ports vented, apply pressure to CYL
1 port. Gradually increase pressure flow of
20 CC/MINUTE until poppet pressure is
relieved. Pressure required at CYL 1 port to
unseat poppet shall not be more than 30
Hold each pressure 3 MINUTES. Leakage
from the CYL 1 or VALVE ports is not
Fill VALVE port with fluid. Cap VALVE port.
Apply each pressure 3 MINUTES. Leakage
from CYL 1 port shall not be more than 1
drop per minute at any pressure.
Slowly apply pressure with CYL 1 and
VALVE ports vented. Observe pressure
required to start piston movement. Pressure
required shall not be more than 12 psig.
(Movement can be observed by placing a
nylon rod against end of poppet through
CYL 1 port.)
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