TM 9-4940-568-34
2-47
Table 2-7. Crane Troubleshooting (CONT).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Test 3.
Remove five function control cover. Refer to paragraph 3-31. Disconnect the line that
comes from the retract fitting to the mast 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 MAST control lever to
attempt to lower mast. 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 erection cylinder. Refer to
paragraph 3-19 or 6-10.
If pressure is not within specifications, repair MAST control valve/shuttle valve
circuit. Refer to paragraph 3-35. If fault is not corrected, repair or replace erection
cylinder. Refer to paragraphs 3-19 or 6-10.
END OF TEST
ERECTION
CYLINDER
TENSION
LINK CYLINDERS
RETRACT
MAST
CONTROL
LEVER
