TM 9-2320-279-34-1
Troubleshooting Malfunctions (Cont)
2-7. TROUBLESHOOTING INSTRUCTIONS (CONT.).
Table 2-3. Troubleshooting (Cont)
Malfunction
Test or Inspection
Corrective Action
MATERIAL HANDLING CRANE (M977, M985, M984A1) (CONT)
11. BOOM RAISES OR LOWERS SLOWLY.
step 1.
Refer to HYDRAULIC SYSTEM troubleshooting.
If problem remains, go to step 2.
Step 2.
Check for damaged lift cylinder lines and damaged lift cylinder.
Replace damaged lift cylinder lines (para 17-2 for M977 and M985) (para 17-2.1 for
M984E1).
Refer to step 6 if lift cylinder appears damaged.
WARNING
Do not loosen both lift cylinder holding valves unless crane is in stowed position
or boom is blocked. Boom will drop and can cause injury or death.
Step 3.
Check for contaminated or damaged lift cylinder holding valve.
Remove, clean, inspect, and install lift cylinder holding valve (para 17-17). Do not
remove lift cylinder.
2-102
Change 3
