Textron Jacobsen AR-5 Technical/Repair Manual

6-10 4181383 First Edition
HYDRAULICS
6
Theory of Operation and
Diagnostic Information
Steering Circuit Schematic and
Theory of Operation
See Figure 6-7.
System Conditions:
• Engine running
• Steering wheel turned to the right or left (left turn
shown)
Hydraulic oil is drawn from the hydraulic oil tank by the
steering section of the gear pump assembly. Before
entering the gear pump assembly, the inlet oil is filtered
by a 100-mesh screen to remove any debris.
Operating-pressure oil is then routed to the IN port of the
steering valve assembly, and oil is applied to the relief
valve, check valve, and steering direction valve.
With the steering wheel in the neutral (straight ahead)
position, the steering direction valve routes all of the
operating-pressure oil out of the steering valve assembly
through the AUX port, supplying operating-pressure oil to
the lift valve assembly. If pressure within the lift system
reaches 1740 psi (120 bar), the relief valve will open,
dumping oil flow back to the hydraulic oil tank through the
return filter and oil cooler. The relief valve will close once
the lift system pressure drops below the relief valve
setting.
When the steering wheel is turned, the steering direction
valve directs operating-pressure oil to one side of the
steering cylinder, moving the piston and steering arms,
turning the rear wheels.
Low-pressure (return) oil from the other side of the
steering cylinder flows through the steering direction
valve and exits the steering valve assembly at the OUT
port. It then flows back to the hydraulic oil tank through
the return filter and oil cooler. The return filter and oil
cooler are equipped with crack bypass valves. If either of
them becomes clogged and restricts oil flow, the valve(s)
will open to allow oil to bypass the return filter (or oil
cooler) to allow oil to flow to the hydraulic oil tank.
A portion of the operating-pressure oil flowing through
the steering direction valve is directed to the lift valve to
supply oil to the raise/lower circuit. (See “Raise Circuit
Schematic and Theory of Operation” on page 6-12.) (See
Lower Circuit Schematic and Theory of Operation on
page 6-14.) The amount of oil directed to the raise/lower
circuit will depend on the position of the steering wheel,
as the steering circuit has priority. The most oil will flow to
the raise/lower circuit when the steering wheel is in the
neutral (straight ahead) position.

Textron Jacobsen AR-5 Specifications

General

Brand	Textron
Model	Jacobsen AR-5
Category	Lawn Mower
Language	English