Lift Circuit Problems - Toro GroundsmasterR 4300-D Service Manual

Lift Circuit Problems

Problem
Single cutting deck raises slowly or not
at all
Cutting decks raise, but will not remain
in the raised position
NOTE: 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.
None of the cutting decks will raise or
lower
NOTE: 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
Single cutting deck lowers very slowly
or not at all
Groundsmaster 4300--D
Possible Causes
Cutting deck has excessive debris buildup.
Lift arm or lift cylinder is binding.
Flow control orifice in lift control manifold for the affected cutting deck is
plugged, stuck or damaged.
Lift cylinder leaks internally.
Lift circuit hydraulic lines or fittings are leaking.
Air exists in lift circuit.
Lift cylinder leaks internally.
Solenoid valve (S2) in lift control manifold leaks.
Oil level in hydraulic reservoir is low (other hydraulic systems are
affected as well).
An electrical problem exists that prevents lift control manifold solenoid
valve operation (see Troubleshooting in Chapter 5 -- Electrical System).
Solenoid valve PRV in lift control manifold is faulty.
Logic cartridge LC in lift control manifold is faulty.
Solenoid valve S2 in lift control manifold is faulty.
Gear pump section (P4) is worn or damaged.
Flow control orifice in lift control manifold for the rear cutting decks
(port C8) is plugged, stuck or damaged.
Lift arm or lift cylinder is binding.
Lift cylinder is damaged.
Flow control orifice in lift control manifold for the affected cutting deck is
plugged, stuck or damaged.
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