Page 19
45-J Desel - Servce & Parts Manual
January 2022
Secton 10 - Hydraulc System
Hydraulic Roadmap
Hydraulic Reservoir
Hydraulic fluid is held in the reservoir for delivery to the pumps and is returned to the reservoir
after use. Returning hydraulic fluid is routed through a filter before entering the reservoir. The
reservoir also serves as the oil cooling device.
Drive Pump
The closed-loop hydrostatic piston-type Drive Pump with infinitely variable proportional control
delivers hydraulic fluid under pressure to the Wheel Motors.
Functions Pump
The gear-type Functions Pump delivers hydraulic fluid under pressure to the Functions Manifold
and provides pressure to the platform and turntable functions, in addition to controlling the axle
cylinders and the brakes.
Main Manifold
The Main Manifold directs the hydraulic fluid to the Boom Lift, Boom Extend and Steering
Cylinders, as well as fluid flow to the Platform Functions Manifold, through the use of
electronically-operated solenoid valves.
Brake/Axle/2-Speed Manifold
The Brake/Axle/2-Speed Manifold directs the hydraulic fluid to the Axle Cylinders, the Brake
Release function and the 2-Speed Pilot function through the use of electronically-operated
solenoid valves.
Platform Functions Manifold
The Auxiliary Manifold provides hydraulic control to the Platform Level, Platform Rotate and Jib
functions.
Turntable Motor
One hydraulic motor turns the turntable, boom and platform in relation to the chassis.
Rotary Manifold
The Rotary Manifold provides hydraulic connection between the turntable and chassis and
allows continuous rotation of the turntable.
Wheel Motors/Brake Hubs
There are four 2-Speed hydraulic wheel motors to provide power to all four wheels. The wheel
motors turn planetary hubs with integral spring-applied, hydraulically-released brakes. The
brakes are released by hydraulic pressure from the Brake/Axle/2-Speed Manifold. The drive
system is hydrostatic; deceleration is provided by the drive motor.
Axle Cylinders
Two hydraulic cylinders control angle of steering axle relative to the frame. The axle cylinders
move freely and allow the axle to float when driving over rough terrain when the platform is
stowed. When platform is elevated or extended, the axle cylinders lock in place to increase
machine stability. Each cylinder has an integral counterbalance valves for load-holding.
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