Section 7.Component Procedures

Model 4700 Maintenance Manual

Hydraulic Fluid Hydraulic Components

Hydraulic Fluid

Changing Fluid

To change the hydraulic fluid, park the truck on a flat surface with the mast tilted back and the forks lowered. Set the parking brake.

1.Disconnect one of the outboard hoses that feeds the auxiliary functions.

2.Direct the hose into a waste container with a capacity >5.5 gallons (21liters). To drain the reservoir, operate an auxiliary function until you hear air in the system.

Operating the pump with the system drained can damage the pump.

3.Turn the key switch OFF and disconnect the battery connector.

4.Remove the floor of the operator compartment to access the reservoir and filter.

5.Remove cap with filter. Remove the filter from the cap.

6.Install a new filter on the cap.

7.Reconnect the outboard hose.

8.Fill the reservoir with new, clean hydraulic fluid. Refer to "Lubrication Specification Chart" on page A-2. Install cap with filter.

9.Install the operator compartment floor.

10.Test to make sure the hydraulic system is functioning correctly.

11.Check to make sure there are no fluid leaks.

Bleeding the Hydraulic System

You must bleed the hydraulic system whenever you:

•Change the hydraulic fluid and filter

•Change a hydraulic hose

•Disconnect a hydraulic fitting

•Notice that the load is bouncing

•Remove a hydraulic cylinder

•Remove a hydraulic pump

•Remove the hydraulic reservoir

TF and TT Masts

1.Reconnect the battery connector and turn the key switch ON. Sit on the seat and lift the forks 6 to 12in. (150 to 300 mm) off the ground.

2. Free Lift Cylinders - Loosen (do not remove) the bleed screw on the lift cylinder to let any air escape. Hold a shop rag close to and beneath the bleed screw to keep any hydraulic fluid from spraying out. When all of the air has escaped and hydraulic fluid starts coming out of the bleed screw hole, securely tighten the bleed screw.

NOTE : Main Lift Cylinders are self-bleeding. Lift and lower the forks several times.

3.Lower the forks all the way to the floor. NOTE : When bleeding the hydraulic system, bleed all cylinders.

4.Bleed the auxiliary system: a.Tilt the mast all the way forward and backward several times. b.If the lift truck has sideshift, shift the carriage all the way to the left and right several times.

5.Check the hydraulic fluid level. Add hydraulic fluid as needed.

Quad Masts

1.Without a load, extend the free lift cylinder and continue to extend the main lift cylinders to 90% of full stroke. Retract all cylinders completely. Repeat three times.

2.Extend the cylinders without a load at 50% lift speed, then build full system pressure at the end of the main lift cylinder stroke. Retract cylinders. Repeat four times.

3.Cycle the mast with a half load (50% mast rated capacity) through full cylinder extension several times. The cylinders should extend smoothly. Repeat the steps if cylinder extension is not smooth.

Publication 1160093, Issued: 20 May 2013