Lift/Lower Circuit Problems - Toro Groundsmaster 4300-D Service Manual

Lift/Lower Circuit Problems

One cutting deck raises slowly or not at all.
One or more cutting deck raises, but does not stay up.
Note: The lift cylinders and control manifold cartridge valves
cannot provide an absolutely perfect seal. The cutting decks
will eventually lower if left in the raised position. At minimum,
the cutting decks should remain in the raised transport
position long enough to safely move from one fairway to
the next.
None of the cutting decks will raise or lower.
Note: The operator must be in the seat or the parking brake
engaged and mow speed limiter must be in mow speed
position in order to lower the cutting decks.
Neither of the rear cutting decks will raise or lower but the
front cutting decks will raise and lower.
One cutting deck lowers very slowly or not at all.
Hydraulic System: Troubleshooting
Problem
• The cutting deck has excessive unwanted elements.
• The lift arm or lift cylinder is binding.
• The flow control orifice in lift control manifold for the affected
cutting deck is plugged, stuck, or damaged.
• The lift cylinder leaks internally.
• The lift circuit hydraulic lines or fittings are leaking.
• Air exists in the lift circuit.
• The lift cylinder for the affected cutting deck(s) leaks
internally.
• The solenoid valve (S2) in lift control manifold is damaged
or leaks.
• The fluid level in the hydraulic reservoir is low (other
hydraulic systems are affected as well).
• An electrical problem exists that prevents lift control
manifold solenoid valve operation (refer to
(page 5–24) or the Electrical Schematic and Wire Harness
Drawings/Diagrams in
• The solenoid valve PRV in the lift control manifold is
damaged.
• The logic cartridge LC in lift control manifold is damaged.
• The solenoid valve S2 in lift control manifold is damaged.
• The gear pump section (P4) is worn or damaged.
• The flow control orifice in lift control manifold for the rear
cutting decks (port C8) is plugged, stuck or damaged.
• The lift arm or lift cylinder for the affected cutting deck is
binding.
• The lift cylinder for the affected cutting deck is damaged.
• The flow control orifice in the lift control manifold for the
affected cutting deck is plugged, stuck or damaged.
Page 4–42
Possible Causes
Troubleshooting
Appendix A (page A–1)).
Groundsmaster
16226SL Rev C
® 4300-D