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4.4 LOSS OF PARALLEL DRIVE
The rubber track systems are driven by hydraulic track drive units. Drives consist of a hydraulic
motor connected to a planetary drive gearbox.
Power is relative to the hydraulic pressure and speed is relative to the hydraulic flow from the
machine's hydraulic circuit. Please refer to the Parts List and Hydraulic Specifications document
for maximum pressure and flow settings of each individual track system. Under recommended
pressure and flow conditions, if tracked undercarriage shows loss of parallel drive and machine
starts slewing, please read below checks that can be made to identify possible causes:
Check 1:
Using pressure and flow testing equipment check the values of the flow and pressure being
applied to the hydraulic motors.
Possible Cause:
If hydraulic pressure and flow being supplied to the motors is different from one another, the
machine hydraulic pressure and flow settings may need to be adjusted.
Check 2:
Test to ensure a pressure is being applied to the brake release function on the gearbox. To
release the brakes, generally pressure ranges between 12 and 50 bar.
Possible Cause:
If the pressure being applied at the brake release port is below the required pressure, do not
attempt to drive the track system. Trying to drive the tracks without releasing the brakes
could result in gearbox failure and void the warranty.
Check 3:
Using pressure testing equipment, test pressure on the return drain line from motor to
ensure back pressure does not exceed 2 bar. Excessive back pressure in the drain can cause
automated switching of motor displacement on integrated motors.
Possible Cause:
Drain Blockage in hydraulic circuit between the motor and the hydraulic tank. If the above
checks have been carried out with no signs of any faults, please contact the helpline for
further assistance.
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