Specifications

Vehicle System Testing & Adjusting 77
Drift Test
Drift is movement of the mast or carriage that is the
result of hydraulic leakage in the cylinders or control
valve. Before testing the drift:
WARNING
Personal injury can be caused by sudden
movement of the mast or carriage. Use wood
blocks and clamps to hold the mast in this
position. Keep hands and feet clear of any parts
that can move.
1. Check the chain adjustment and tilt cylinder
alignment and make necessary adjustments.
2. Lift the mast approximately 762 mm (30 in). Use
wood blocks and clamps to hold the mast in this
position.
3. Check the mast hinge bolts to make sure they are
tight.
4. Remove the blocks and clamps and lower the mast.
Drift Test For Lift System
1. Secure a rated capacity load on the forks of the lift
truck. Operate the lift truck through a complete lift
and tilt cycle until the oil is at normal temperature
of operation, 45 to 55 °C (113 to 131 °F).
2. Put the mast in a vertical position.
Raise a rated capacity load to a sufficient height to
test the lift cylinders.
3. Measure any drift of the carriage for a ten minute
period. Drift for all models shall not exceed 100.0
mm (4.00 in).
Drift Test For The Tilt System
1. Put a rated capacity load on the forks on the lift
truck. Operate the lift truck through a complete lift
and tilt cycle until the oil is at normal temperature
for operation, 45 to 55 °C (113 to 131 °F).
2. Put the mast in a vertical position. Raise a rated
capacity load to a height of 2.5 meters (8.2 ft). In
the case of trucks with less than 2.5 meters (8.2 ft)
height extension, raise the load to the truck’s
maximum height.
Tilt Drift Check.
3. The tilt drift is measured as the charge in the tilt
cylinder stroke. Measure any drift of the mast for
ten minute period.
Drift for shall not exceed 35.5 mm (1.40 in).