IV-28
HYDRAULIC UNITS
HST PUMP
Neutral Adjustment of the Pump
WARNING
• Be sure to do these adjustments on the level
ground.
• The hydraulic oil and the tank are hot and
under pressure at operating temperature.
• Never adjust the pump immediately after
the engine stops to prevent bodily injuly, be-
cause all the components are hot.
• Do not allow hot oil and components to con
-
tact your skin.
• When removing the hydraulic hose, slowly
loosen the hydraulic hose.
In this adjustment, the tie bolt of the controlling sec-
tion should be adjusted so that the pressures on both
sides of the turbo piston become equal.
1. Connect the hydraulic hoses to the gauge ports
to make the pressures on both sides of the servo
piston equal.
• Hydraulic pump P1 .....
M4 and M5.
• Hydraulic pump P2 .....
M14 and M15.
2. Install the pressure gauges to the ports to mea-
sure the circuit pressure.
• Hydraulic pump P1 .....
A1 and B1.
• Hydraulic pump P2 .....
A2 and B2.
3. Start the engine and run it at the rated rotational
speed.
4. Loosen the adjusting seal nut (18) of the hydrau-
lic pump and turn the tie bolt (16).
• Turn the tie bolt (16) until the readings of the
two pressure gauges become equal.
5. Turn the tie bolt (16) until the reading of one
pressure gauge becomes higher than that of the
other pressure gauge.
• Record the position of the tie bolt.
6. Turn the tie bolt (16) until the reading of the
other pressure gauge becomes higher than that
increased in 5 above.
• Record the position of the tie bolt.
S3F341
16
18