TM 9-2320-279-34-1
Troubleshooting Malfunctions (Cont)
Table. 2-3. Troubleshooting (Cont)
Malfunction
Test or Inspection
Corrective Action
MATERIAL HANDLING CRANE (M977, M985, M984E1) (CONT)
10.
BOOM WILL NOT TELESCOPE IN.
Step 1. Check for damaged extension cylinder lines.
Replace damaged extension cylinder lines (para 17-2 for M977 and M985)
(para 17-2.1 for M984E1).
Step 2. Check for contaminated or damaged extension cylinder holding valve.
Remove, clean, inspect, and install extension cylinder holding valve (para 17-19
for M977 and M985) (para 17-19.2 for M984E1). Do not remove extension cylinder.
Step 3. Check for overload sensor switch adjustment (para 17-33 for M977 and M985) (para 17-33.1
for M984E1).
If switch(es) cannot be adjusted, replace (para 6-12 for M977 and M985)
(para 6-12.1 for M984E1).
Step 4. Check for contaminated or damaged telescope directional control valve spool.
Remove, clean, inspect, and install directional control valve spool (para 17-28 for
M977 and M985) (para 17-28.4 for M984E1).
Step 5. Check for damaged boom extension sections and cylinder.
Remove extension No. 1 (para 17-12 for M977 and M985) (para 17-12.1 for
M984E1), extension No. 2 (para 17-13 for M977 and M985) (para 17-13.1 for
M984E1), and extension cylinder (para 17-18 for M977 and M985) (para 17-18.1 for
M984E1).
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