H Y D R A U L I C
S Y S T E M
T E S T I N G
A N D
A D J U S T I N G
Lift, lower, dump and tilt back the bucket several
Watch the cylinders as they are extended and
retracted. Movement must be smooth and
Listen for noise from the pump.
Listen for the sound of the relief valves. They
must not open except when the cylinders are
fully extended or retracted, when the bucket is
Watch the operation of the bucket positioner
and lift kickouts.
The lift control lever has detents in the RAISE and
The tilt control lever has a detent in the TILT
BACK position (only when the bucket is between full
dump and the bucket angle to dig).
Lift And Tilt Cylinder Drift Tests
The drift rates will change with different condi-
tions of the hydraulic components as well as with the
operation, the type of bucket (empty or loaded),
hydraulic oil temperature, etc.
The values shown are for an empty bucket. Before
measuring drift on the cylinder rod, the cylinders
must be extended at least five times. Check the oil
To check the lift circuit, lift the bucket to maxi-
mum height and move the control lever to the HOLD
position. Measure the distance (and check the time)
that the cylinders retract, with the chart.
NOTE: The drift distances in the charts are for new
APPROXIMATE LIFT CYLINDER DRIFT
38 ~ 3°C
49 f 3cc
66 * 3°c
(100 i 5°F)
(120 f5° F)
(150 L 5°F)
To check the tilt circuit, lift the bucket to maxi-
mum height, and move the lift control lever to the
HOLD position. Activate the tilt circuit until the
bucket is at the angle to dig (almost level) and move
the tilt control lever to the HOLD position. Measure
the distance (and check the time) that the cylinder
retracts, with the chart.
APPROXIMATE TILT CYLINDER DRIFT
38 ~ 3°C
49 f 3°c
66 * Bc
(100 Y 5°F)
(120 f5° F)
If the cylinder drift is too much:
1. Check the make-up valves in the lift and tilt
2. Check the condition of the valve spools in the lift
and tilt control valve.
3. Check the piston seals in the cylinders.
Attachment Cylinder Drift
The attachment cylinders will drift in the close or
lower direction because of an orifice (to the tank) in
the line from the rod end of the attachment
Lift And Tilt Cylinder Speed Tests
Start and run the engine at high idle rpm. Lift and
lower the lift arms again and again to get an increase
in the temperature of the hydraulic oil.
The oil in the system must be SAE 10 and at a
temperature of 65 ± 3°C (150 ± 5°F) to get accur-
ate test results. All speed tests are made with the
engine at high idle. The speeds in the following chart
are those of machine equipped with a general pur-
TILT CYLINDER SPEED TEST
DUMP (full tilt back-to-full
dump, bucket at maximum
height, empty bucket)
2.0 * 0.5
If the travel times are not correct:
1. Check the pump efficiency.
2. Check the setting of the relief valves.
3. Check the make-up valves in the lift and tilt
4. Check the valve spools in the lift and tilt control
5. Check the piston seals in the cylinders.