Cause / 702
1. Plugged suction screen. 2. Bypassing lowering valve. 3. Bypassing check valve. 4. Bypassing relief valve. 5. Pump sucking air. Due to: A) Pump shaft seal is worn. B) Pump shaft is corroded. C) Loose or cracked suction stuf or line. 6. Low oil level. 7. Overloading lift. 8. External oil leak.
Repair / 702
1. Replace or clean suction screen. 2. clean or replace lowering valve. 3. Clean or replace check valve. 4. Clean or replace relief valve. 5. Tighten all suction line fittings. A) Replace pump shaft seal. B) Replace pump. C) Repair or replace. 6. Fill tank with proper weight hydraulic oil. 7. Check vehicle weight and/or balance vehicle weight on lifts. 8. Repair external leaks.