• If the screw is turned to the right the pres- sure increases.
• If the screw is turned to the left the pressure reduces.
• Quantity of adjustment per turn of the screw:
Approx 5.5MPa.
After required pressure is achieved, hold adjustment screw (1b) and tighten the lock nut (1a). (Torque of lock nut (1a) 12+/-2Nm)
Symbol Part No. Part name
J
1 799-101-5002 Hydraulic tester 790-261-1204 Digital hydraulic tester 2 799-101-5220 Nipple (10 × 1.25 mm)
07002-11023 O-ring
J2
1a
1a 1b
TESTING AND ADJUSTING Measuring and adjusting quick coupler control valve output pressure
Blank for technical reason
Testing travel motor relief pressure TESTING AND ADJUSTING
Testing travel motor relief pressure
• The travel motor has two pressure relief valves which con- trol the deceleration of the machine. One operates in for- ward travel and one in reverse.
• Set pressure = 42 MPa (428 kg/cm²)
Measuring travel motor relief pressure
Oil temperature should be 45 - 50°
• Fit a 600 kg/cm² pressure gauge to port Mb on the front trav- el motor.
• Test the machine on a downhill slope with a smooth surface and long enough to allow the pressure to stabilize. If the slope is steep (more than 5 degrees) test in LOW mode, oth- erwise test in HIGH mode.
• Travel forward at approximately half maximum speed (for the selected mode), then release the travel pedal. Read the pressure gauge after the pressure stabilizes.
NOTE
Always use a gauge which can be read safely while the machine is travelling.
Alternatively use a gauge which records the pressure reading and study the data after the machine has been stopped.
• If it is necessary to check the other relief valve then swap the relief cartridges between ports and check the second re- lief by travelling the machine forward.
• it is extremely dangerous to travel the machine at high speed in reverse - always check the relief valves as shown above.
Mb
(Ma opposite side)
TESTING AND ADJUSTING Adjusting travel motor relief pressure
Adjusting travel motor relief pressure
The valve controlling deceleration of forwards travel is located on the left side of the motor (facing forward) the same side as port Ma.
The valve controlling deceleration of reverse travel is located on the right side of the motor (facing forward) the same side as port Mb.
• Remove seal and cap from the valve.
• Loosen locking nut.
• Turn adjustment screw clockwise to increase, and counter- clockwise to decrease the pressure.
• Tighten locknut.
NOTE
The set pressure cannot be measured whilst making an adjust- ment.
Always repeat the measurement to check the set pressure after adjusting.
Testing propshaft speed TESTING AND ADJUSTING
Testing propshaft speed
Measuring rotating speed of propshaft
• Lift the wheels from the ground using the blade and outrig- gers or work equipment.
• Set the machine to high idle.
• Measure in CREEP and LO travel speeds.
• Gently depress the travel pedal to full stroke.
Hazard from rotating wheels exists.
• Allow the speed of the propshaft / wheels to stabilize for a few minutes then measure the rotating speed of the prop- shaft using an optical tachometer.
• Gently release the travel pedal to stop the wheel rotation.
• Always change rotating speed slowly. Sudden release of the travel pedal could damage the transmission or motors.
• Judgement table
NOTE
With the machine in ’Travel Speed-Hi’ it is not possible to judge propshaft speed. In this condition the propshaft speed will appear to hunt. This phenomenon is caused by the machine overspeed control logic and is not a fault.
Propshaft speed in RPM Oil temperature 45 ~ 50°C
Check Item Unit Standard Remarks
Travel Speed - CREEP A Mode
rpm
198 +/-5% If too high check travel EPC valve.
Travel Speed - LO A Mode 990 +/-5%
If the speed is out of tolerance refer to troubleshooting section. Do not attempt to adjust travel motor dis- placement.
TESTING AND ADJUSTING Testing transmission clutch control circuit
Testing transmission clutch control circuit
Description
The transmission contains two clutches which engage HI and LO gear. The clutches are engaged or disengaged by the clutch control solenoid valve. Energising the clutch control solenoid valve will select LO gear and de-energising the solenoid valve will select HI gear. When the solenoid valve is energised, port Q is connected to tank (i.e. no pressure) and port P is pressurised.
In this condition the LO gear clutch (large diameter) is engaged and the HI gear clutch (small diameter) is disengaged. If the clutch control solenoid is de-energised, then port P is connected to tank and port Q is pressurised. In this condition, the HI gear clutch is engaged the LO gear clutch is disengaged.
LO gear = High torque (LO speed) HI gear = Low torque (HI speed)
The actuation pressure for the transmission clutches is supplied from an accumulator via a pressure reducing valve and park brake solenoid valve mounted in the power brake valve. The park brake solenoid valve must be energised to feed the actua- tion pressure to either HI or LO clutch. With the park brake valve de-energised, both clutches are engaged and so the park brake is engaged.