TM 9-2350-256-20-1
UNIT MAINTENANCE
RECOVERY VEHICLE, FULL TRACKED: MEDIUM, M88A1
NSN 2350-00-122-6826, EIC AQA
MAIN HYDRAULIC PUMP TROUBLESHOOTING PROCEDURE
INITIAL SETUP:
Tools and Special Tools
References
Tool kit, general mechanic's (item 59, WP 0490 00)
WP 0303 00
WP 0416 00
Materials/Parts
WP 0418 00
Compound, cleaning (item 9, WP 0489 00)
Troubleshooting Procedure
Main Hydraulic Pump
Symptom
Main hydraulic pump malfunctioning.
Malfunction
Main hydraulic pump fails to operate.
Do steps 1 thru 5.
Main hydraulic pump fails to develop sufficient pressure. Do steps 3 thru 6.
Main hydraulic pump is noisy during operation. Do steps 3 thru 6.
CORRECTIVE ACTION
1.
Ensure system selector control lever is in the MAIN position. If problem persists, go to step 2.
2.
Test for defective power control valve or restricted hose. Remove hose No. 66 from mechanical
transmission (see WP 0416 00). With mechanical transmission drive shaft rotating, and power control
valve lever placed in ON position, oil should flow from hose.
a.
If no oil flows from hose, check hose for damage or restriction and replace as necessary (see
WP 0416 00). If oil flow cannot be restored, go to step 4. If oil flows, go to step 3. If mechan-
ical transmission drive shaft does not rotate, notify Direct Support Maintenance.
b.
If no oil flows from hose after checking hoses and replacing as necessary, this indi-
cates a defective power control valve. Notify Direct Support Maintenance.
3.
Inspect main hydraulic pump drive shaft. If shaft is rotating, go to step 4. If shaft is not rotating, go to
step 5.
WARNING
Do not attempt to loosen or tighten hydraulic fittings or lines when system is pressurized. Severe injury
or death to personnel may result.
4.
Inspect all hydraulic hoses and connections for visible indication of leaks or damage. Replace hydraulic
hoses and tighten fittings as necessary (see WP 0416 00). If problem persists, go to step 5.
5.
Inspect main hydraulic pump for broken or damaged shaft coupling. Tighten bolts and/or replace
missing bolts and lockwashers (see WP 0416 00). If additional damage is present or main hydraulic
0037 00-1
