Service Manual

Topdresser 1800 & 2500 Hydraulic SystemPage 3 – 11
Topdresser 2500 Operation: Switch Off
While being towed in the forward direction with the Top-
dresser control handle switch in the OFF position, the
wheel motors act as pumps to provide hydraulic flow for
the system. This flow from the wheel motors is directed
through the control manifold and solenoid valve S1 (not
energized) to bypass the brush and conveyor motors.
Flow is then directed to the charge motor/pump assem-
bly causing the charge motor to rotate. The charge mo-
tor rotation in turn rotates the charge pump which
provides charge flow to fill the hydraulic system to the
wheel motors. Charge pressure is limited by the charge
relief valve (R2) located in the control manifold.
If the Topdresser is towed in the reverse direction, flow
from the wheel motors will reverse. Check valves CV3
and CV1, however, are placed in the hydraulic manifold
to prevent reverse flow through the hydraulic system.
Hydraulic
System