TM 9-4940-568-34
2-63
Table 2-7. Crane Troubleshooting (CONT).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Test 2.
Remove five function control cover. Refer to paragraph 3-31. Disconnect the line that
comes from the telescopic cylinder retract fitting on telescope control valve. Install a flow
meter in line between control valve and line. Open pressure control valve fully by turning
control knob counter clockwise to DECREASE. Start FRS. Have assistant operate
TELESCOPE control lever to attempt to retract boom. Slowly close pressure control valve
by turning knob clockwise to INCREASE. Create 3,000 - 3,200 psi (20,684 to 22,063 kPa)
working pressure.
If pressure is within specifications, repair or replace boom telescopic cylinder.
Refer to paragraph 3-15 or 6-11.
If pressure is not within specifications, repair telescopic control valve/shuttle valve
circuit. Refer to paragraph 3-35. If fault is not corrected, repair or replace boom
telescopic cylinder. Refer to paragraph 3-15 or 6-11.
END OF TEST
TELESCOPE
CONTROL
LEVER
RETRACT
