NMC-WOLLARD 2021Truax Blvd., Eau Claire, WI 54703, Phone (715) 835-3151, Fax (715) 835-6625
M140 Tow Tractor Manual No. 46054
PAGE 2-1
CHAPTER 2 MAINTENANCE
2 TROUBLESHOOTING
AUGUST 31, 2008
2. TROUBLE SHOOTING
Perform lockout/tagout procedures before adjusting, lubricating, cleaning
or otherwise servicing. Failure to do so could result in unexpected startup and could
cause serious injury or death.
To minimize risk of serious injury or death, follow these hydraulic
servicing precautions:
• Follow all necessary lockout/tagout procedures.
• Hydraulic systems have residual, stored pressure. Relieve all pressure from the
hydraulic system before servicing.
•
•
seek medical attention.
• Wear eye protection when servicing hydraulic components or systems.
• Keep all hoses and connections in good serviceable condition. Check before start-up
and periodically during operation.
• Do not investigate for leaks with hands. Use a large piece of cardboard.
•
2.1 STEERING SYSTEM OVERVIEW - USED WITH AT545 TRANSMISSION
The steering gear is powered by a gimbal-mounted, double-acting hydraulic
cylinder mounted on the front axle. The control unit is actuated directly by the
Turning the steering wheel actuates the rotary valve in the power steering unit.
As the valve opens, hydraulic oil travels into a metering motor within the power
steering unit, then out from the motor, through the valve, and out to the retract side
turns, it moves a feedback linkage that returns the rotary valve to center and locks
the steering cylinder in position. The metering motor therefore ensures that the
steering cylinder is precisely controlled by the command received from the steering
wheel.
In the event of a power failure, steering can be done manually by spinning the
steering wheel. In this case, steering wheel movement turns the metering motor
directly through the feedback linkage. The motor is then used as a pump to force
oil into the cylinder, while drawing oil into the suction side (through check valve)
from the return line.
To Next Page
Loading...
