1.115 HYDRAULICS Extension, crowd, compensator and lift cylinder (49), (51), (53) and (54) 7. Remove the grub screw (5) from the piston (6) unscrew and remove the piston from the piston rod. Servicing The extension, crowd, compensator and lift cylinders are of the same internal construction; the only difference is the size. External differences consist of end fittings and piping to the cylinder. 8. Remove the spacer (7) (if fitted) from the piston rod. 9. Remove and discard all seals spacers and O-rings (8), (9), (10), (11) & (12) from the piston. The hydraulic cylinders are heavy. Take care when handling cylinders, to avoid damage to components and injury to personnel. 10.
Remove and discard all seals and spacers (13), (14), (15), (17), (18) & (19) from the gland nut (16). The dismantling and assembly procedure is based on the extension cylinder; all other cylinders are similar. The load control valve is factory set and should not be dismantled or adjusted except for resealing. Dismantling 11. If the load control valve (20) is faulty, remove by unscrewing, A new valve must be fitted. 1. Clean the exterior of the cylinder with a suitable solvent and dry with compressed air. Do not use cloths or paper towels to dry component. Assembly 2. Drain as much hydraulic fluid as possible from the cylinder into a suitable container before dismantling. 1.
Assemble the hydraulic cylinder in the reverse order to dismantling. 3. Support the cylinder on ‘V’ blocks; make sure that when the piston is removed the components are not damaged. 2. Use new O-rings, seals and spacers during assembly. If compressed air is used to extend the piston assembly, the gland nut (17) must not be removed. release all pressure before the gland nut is removed. 3. Make sure all old Loctite is removed from the threads of the piston, piston rod and grub screw before assembly. Apply Loctite sealant to threads of piston rod and securely screw piston to piston rod before fitting grub screw. 4.
When the piston assembly is difficult to extend, a compressed air supply may be used to pressurize the cylinder. Use only the minimum pressure necessary to extend piston. 4. Lubricate O-rings, seals and spacers with clean hydraulic oil before and during assembly. 5. Torque tighten the components in accordance with Table on page 1.116. 5. Using a suitable spanner, unscrew the gland assembly (1) from the cylinder (2). 6. Withdraw the piston rod (3) complete with piston assembly (4) from the cylinder (2). If necessary, fit a suitable size pin through the eye-end of the piston rod and carefully tap with a soft-faced hammer to remove piston rod.