Hyster Forklift HR 45-36

NOTE: Only use plugs that have been cleaned in solvent.

NOTE: In the event that seals are missing, check manifold for missing seals and remove.

NOTE: Cartridge valves are not field serviceable with exception of external seals and electrical solenoids. In event of a defective component, completely replace valve.

NOTE: Check load holding valve for cracks. If there are cracks in load holding valve, the load holding valve must be replaced.

The valve seals are serviceable parts of the load holding valve. Use the following procedures for repair:

Unscrew the cartridge valve from the load holding valve. See Figure 9.

Check that all seals are attached to cartridge valve.

Install a temporary plug in place of cartridge valve.

Sign off on the disassembly process

NOTE: The pressure reducer valve is adjustable. If a setting pressure is not within specifications, adjust the valve.

Lower lift cylinders completely

Connect a 0 to 7 MPa (0 to 1015 psi) gauge to check port MPLT

Start engine. Run engine until temperature of hydraulic oil is 55 to 65 C (130 to 150 F). Check pressure at idle speed.

NOTE: Correct measurement can be achieved during movement (flow) of the main spool.

Check if pressure is 5 MPa (725 psi)

If pressure is not correct, adjust pressure reducer valve

!WARNING: Cleaning solvents are flammable and toxic and can cause skin irritation. When using cleaning solvents, always follow the solvent manufacturer’s recommended safety procedures. Wear protective goggles or a face shield to prevent eye injuries.

Clean all parts of pump with solvent. Use compressed air to dry parts. Do not use a cloth to dry parts. Pieces of cloth can cause restrictions in hydraulic system.

Inspect gear assemblies and housing parts for wear and damage. Replace a damaged or worn hydraulic pump. If gears are replaced, they must be replaced as matched sets.

!NOTE: Some pump bodies will show gear marks where the gears rotate because of the small clearances between parts. These gear marks do not indicate a worn or damaged pump unless the pump will not supply the volume and pressure shown in the Specifications.

Sign off on the hydraulic pump maintenance

NOTE: The relief valves in the main manifold, main control valve, and flow amplifier are adjustable. If a relief pressure is not within specifications, adjust the relief valve.

Upload a photo of the correct gauge used on the check ports as per Table 2

Enter the temperature of hydraulic oil

Is the pressure gauge according to the specifications shown in Table 3?

To adjust a relief valve setting, remove cap. Loosen lock nut and use an Allen wrench to turn adjuster screw. Turn adjuster screw clockwise to increase pressure.

To lower pressure, first lower pressure below required value by turning adjuster screw counterclockwise and then increase pressure to required level. When relief pressure is correct, tighten lock nut and install cap.

Is the setting correct after tightening the lock nut?

Sign off on the relief valve check

Component/valve lubricated with clean hydraulic oil

Component/valve or switch installed and torqued to value listed in the Torque Specifications

Sign off on the Boom Extension Circuit Assemble