Toro Reelmaster 3100-D Service Manual page 96

Raise Cutting Units
Hydraulic System: Hydraulic Flow Diagrams
The gear pump (P2) is directly coupled to the hydrostat through gear pump
(P1). It supplies hydraulic pressure (charge pressure) for raising and lowering
the cutting units, operating the sidewinder unit, and replenishing the closed
loop traction circuit (charge pressure). The pump takes its suction directly from
the hydraulic tank.
During conditions of not lifting or lowering cutting units, flow from the gear pump
(P2) is by−passed through the power steering valve, 2-spool valve, and hydraulic
manifold directly to the hydrostat and the charge relief valve. Flow then returns
to the hydraulic tank.
When the cutting units are to be raised, the 2-spool valve is positioned by
moving the cutting unit shift lever to RAISE. Flow is directed to cap ends of
the lift cylinders. Hydraulic pressure against the cylinder pistons moves their
shafts causing the cutting units to raise. At the same time, the pistons push the
hydraulic fluid out of the lift cylinders and back through the hydraulic manifold
to the hydrostat.
When the cutting unit shift lever is released, spring action returns the valve to its
original position and by−passes flow back to the hydrostat stopping lift cylinder
movement. The cylinder position is locked in place by the load holding checks
in the lift control valve.
Page 5–20 Reelmaster ® 3100-D/3105-D
20252SL Rev A