Lift/Lower Circuit Problems - Toro Groundsmaster 5900 Series Service Manual

Lift/Lower Circuit Problems

Groundsmaster ® 5900 & 5910
16227SL Rev B
Problem
Cutting decks will not raise.
Note: To raise a cutting deck, the engine must
be running. Also, the operator seat has to be
occupied or the parking brake must be applied
with the traction pedal in neutral.
Note: When the engine is running below 2000
RPM, only one deck can be raised at a time.
Cutting decks raise, but will not stay up.
Note: Lift cylinders cannot provide an
absolutely perfect seal. A cutting deck will
eventually lower if left in the raised position
during storage.
Cutting decks will not lower.
Note: To lower a cutting deck, the seat must
be occupied and the traction speed must be in
the LOW (mow) position.
Side cutting deck drops too fast.
Side cutting deck drops too slow.
Possible Cause
Engine RPM is too low.
Hydraulic oil level in reservoir is too low (other
hydraulic systems are affected as well).
Lift arm pivots are binding.
Lift cylinder is damaged.
An electrical problem for the affected deck
exists (see
6–1)).
Solenoid valve in steering/deck lift manifold for
the affected deck is faulty.
Pressure compensator valve (LC) in
steering/deck lift manifold is faulty.
Final gear pump section for lift circuit is worn or
damaged (a worn or damaged final gear pump
section will also affect the traction (charge) and
steering circuits).
Lift circuit hydraulic lines or fittings for the
affected deck are leaking.
Lift cylinder for the affected deck is worn or
damaged.
Solenoid valve in steering/deck lift manifold
for the affected deck (S4, S6, S9) is leaking
or damaged.
An electrical problem for the affected deck
exists (see
6–1)).
Lift arm pivots for the affected deck are binding.
Lift cylinder for the affected deck is damaged.
Counterbalance pressure is excessive (all
cutting decks are affected).
Solenoid valve in steering/deck lift manifold for
the affected deck is faulty.
Excessive debris buildup on the affected
cutting deck.
Orifice in steering/deck lift manifold for the
affected deck (OR3, OR7) is missing or
damaged.
Orifice in steering/deck lift manifold for the
affected deck (OR3, OR7) is plugged or faulty.
Lift arm pivots for the affected deck are binding.
Lift cylinder for the affected deck is worn or
damaged.
Page 3–7
Chapter 6: Electrical System (page
Chapter 6: Electrical System (page
Troubleshooting: