Finding and Solving Problems

Please read and observe the HYDRAULIC PRODUCT SAFETY PAGE before proceeding further. Your safety is important to us!

Gradual or sudden loss of pressure or flow resulting in a loss of power is common in hydraulic system failure.

Any one of the system’s components may be at fault. These step-by-step procedures should help you locate and remedy the problem quickly.


  1. SYSTEM INOPERATIVE
    • No oil in system, insufficient oil in system. Fill system. Check for leaks.
    • Wrong oil in system. Refer to specifications. Change oil.
    • Filter dirty or clogged. Drain oil and replace filter or filter element.
    • Oil line restriction. Oil lines dirty or collapsed. Clean or replace.
    • Air leaks in pump suction line. Repair or replace as necessary.
    • Worn or dirty pump. Clean, repair or replace. Check alignment. Check for contaminated oil. Drain and flush system.
    • Badly worn components (valves, cylinders, etc.) Examine and test for internal or external leakage. Replace faulty components. Check for cause of wear.
    • Leakage. Check all components, particularly the relief valve for proper settings. Refer to technical manuals.
    • Excessive load. Check unit specifications for load limits.
    • Slipping or broken pump drive. Repair or replace belts, couplings, etc. Check for proper alignment or tension.
  2. SYSTEM OPERATES ERRATICALLY
    • Air in system. Check suction side of system for leaks. Repair.
    • Cold oil. Allow ample warm-up period.
    • Dirty or damaged components. Clear or repair as necessary.
    • Restrictions in filters or lines. Clean and/or replace elements or lines.
  3. SYSTEM OPERATES SLOWLY
    • Oil viscosity too high, cold oil. Allow oil to warm up before operating machine.
    • Low pump drive speed. Increase engine speed (check manual for recommendations.)
    • Air in system. Check suction side for leaks. Repair.
    • Badly worn pump, valves, cylinders, etc. Repair or replace as needed.
    • Restrictions in filters or lines. Clean and/or replace elements or lines.
    • Improper adjustments. Check orifices, relief valves, etc. Adjust per manual.
    • Oil leaks. Tighten fittings. Replace seals or damaged lines.
  4. SYSTEM OPERATES TOO FAST
    • Wrong size or incorrectly adjusted restrictor. Replace or adjust as necessary.
    • Engine running too fast. 
    • Reduce engine speed.
  5. OVERHEATING OF OIL IN SYSTEM
    • Oil passing thru relief valve for excessive time. Return control valve to neutral when not in use.
    • Incorrect oil, low oil, dirty oil. Use recommended oil, fill reservoir, clean oil, replace filter elements.
    • Engine running too fast. Reduce engine speed.
    • Excessive component internal leakage. Repair or replace component as necessary.
    • Restriction in filters or lines. Clean and/or replace elements or lines.
    • Malfunctioning oil cooler. Clean or repair.
    • Insufficient heat radiation. Clean dirt and mud from reservoir and components.
    • Malfunctioning component. Repair or replace.
    • Reservoir too small. Recommended size is 1 1/2 times pump gpm.
  6. FOAMING OF OIL
    • Incorrect, low or dirty oil. Replace, clean or add oil as needed.
    • Air leaks. Check suction line and component seals for suction leaks. Replace.
  7. NOISY PUMP
    • Low oil level, incorrect oil, foamy oil. Replace, clean or add oil as needed.
    • Suction line plugged or too small, inlet screen plugged. Clean or replace. Follow instructions packed with unit.
    • Use of pipe fitting in inlet. Replace with correct fitting.
  8. BLOWN SHAFT SEAL
    • Pump: wrong pump shaft rotation. Replace seal. Refer to installation instructions.
    • Motor: failure to hook up drain line. Replace seal. Refer to installation instructions.
  9. LEAKY PUMP OR MOTOR
    • Damaged or worn shaft seal. Replace seal. Check for misalignment.
    • Loose or broken parts. Tighten or replace.
  10. LOAD DROPS WITH CONTROL VALVE IN NEUTRAL
    • Leaking cylinder seals or fittings. Replace worn parts.
    • Control valve not centering when released. Check linkage. Check for spool binding. Repair.
  11. CONTROL VALVE DOES NOT CENTER (Binding)
    • See Hydraulic Product Safety sheet.
    • Valve linkage misaligned. Repair.
    • Tie-bolts too tight (stack valves). Loosen as necessary.
    • Valve damaged. Repair or replace.
    • Handle bracket screws loose. Tighten.
  12. CONTROL VALVE LEAKS EXTERNALLY
    • Tie-bolts too loose (stack valves). Tighten as necessary.
    • Seals damaged or worn. Replace.
    • Back pressure or restriction in tank line. Check quick couplers. Use power beyond when necessary.
    • Cracked port or body. Replace. (see Hyd. Prod. Safety)
  13. CYLINDER LEAKS EXTERNALLY
    • Seals damaged or worn. Replace.
    • Rod damaged. Replace.
  14. CYLINDER LOWERS WITH VALVE IN “METER UP” POSITION
    • Damaged or leaky load check. Replace check.
    • Leaking cylinder seal. Replace seal.
    • Use of a valve without loadcheck. Replace with recommended valve.