TM10-3930-660-20 18-3. HYDRAULIC  SYSTEM -  SERVICE  (Cont’d) NOTE If pump (1) will not pump oil after purging, further troubleshooting is required. 2. CHECK HYDRAULIC OIL LEVEL, FILL HYDRAULIC RESERVOIR AS REQUIRED, AND CHECK FOR LEAKS, LO10-3930-660-12. PURGING AIR FROM TANDEM GEAR PUMP CAUTION Do not attempt to purge sections (a) and (b) separately. Always purge both sections of pump whenever purging is necessary. Failure to purge pump as directed in this section may result in severe damage to pump. NOTE The hydraulic tandem gear pump (5) has two sections, large and small. The large section (a) supplies hydraulic pressure to the boom extend cylinder, boom hoist cylinder, and steering system. The small section (b) supplies hydraulic pressure to the brake system and the frame  tilt  cylinder. 1. PURGE AIR FROM PUMP (5). a. Loosen but do not at elbow (7). b. Loosen but do not at elbow (9). Place suitable container remove hose (6) remove hose (8) under pump (5) to catch any oil lost during purging process. 18-4