Gradall 534B (9020-7317) Service Manual - Manual (Page 70)

GRADALL LOED MATERIAL HANDLER
534B
SYSTEM OPERATION
FORWARD/REVERSE LEVER
(Neutral)
When Forward/Reverse Lever is in neutral
position, electrical contacts are not made at the
Fwd/Rev Switches (J) and the oil flow in the circuit
is as follows:
Oil from reservoir (A) is drawn into the main pump
section (B). It then flows to the priority valve (D)
where a portion is available for the steering circuit.
First, the oil is exposed to the circuit main relief
valve (C) which is set at 3000 psi. The oil leaves the
priority valve and goes into the Forward/Reverse
Valve (E). Since it has not been activated from the
Fwd/Rev Switches (J) the Fwd/Rev Pilot Pressure
Control Valve (F) keeps it in neutral and the oil
passes thru and goes back to the reservoir.
FORWARD/REVERSE LEVER
(Shifted)
With the Fwd/Rev control lever shifted forward,
1st, 2nd or reverse, electrical contact is made at the
Fwd/Rev Pressure Control Valve (F) and
depending on the position (forward or reverse) pilot
oil is sent to the end caps of the Fwd/Rev Valve (E).
The plunger shifts and oil is routed back to the rear
drive motors (L).
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