TM  10-3930-638-24&P Section VI. HYDRAULIC LIFT SYSTEM MAINTENANCE This section contains the information you’ll need to maintain the: Control valve Hydraulic  cylinders Mast and carriage assembly It gives you instructions on how to troubleshoot problems and repair or replace the components that are within the scope of direct support maintenance. Para Para Troubleshooting Index . . . . . . . . . . . . . . . . . . . 3-28 Rotation Cylinder Assembly . . . . . . . . . . . . . 3-30d Hydraulic Lift System Troubleshooting . . . . . . . . 3-29 Lift Cylinder Assembly . . . . . . . . . . . . . . . . . 3-30e Hydraulic Lift System Maintenance . . . . . . . . . . . 3-30 Mast Assembly Maintenance. . . . . . . . . . . . . . . . 3-31 Control Valve . . . . . . . . . . . . . . . . . . . . . . . 3-30a Carriage Assembly . . . . . . . . . . . . . . . . . . . . 3-31a Tilt Cylinder Assemblies . . . . . . . . . . . . . . . . 3-30b Side Shifter Frame and Rotation Bearing . . . . . 3-31b Sideshift Cylinder Assembly . . . . . . . . . . . . . 3-30c Inner and Outer Mast . . . . . . . . . . . . . . . . . . 3-31c 3-28. TROUBLESHOOTING SYMPTOM INDEX Para/Malfunction   Page HYDRAULIC  LIFT  SYSTEM Unable to lift a load (all other functions normal) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29/1 3-194 Load drifts down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29/2 3-197 Unable to sideshift load (all other functions normal) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29/3 3-197 Sideshift cylinder assembly operation sluggish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29/4 3-198 Unable to tilt load (another functions normal) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29/5 3-199 Tilt cylinder assemblies operation sluggish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29/6 3-201 Unable to rotate load (another functions normal) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29/7 3-201 Rotation operation sluggish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29/8 3-202 3-29. HYDRAULIC LIFT SYSTEM TROUBLESHOOTING MALFUNCTION TEST  OR  INSPECTION CORRECTIVE   ACTION 1. UNABLE TO LIFT A LOAD (ALL OTHER FUNCTIONS NORMAL) NOTE After completion of each check, lower forks until resting on ground. Then, turn engine off. 3-194