Lift/Lower Circuit Problems - Toro Greensmaster 3120 Service Manual

Lift/Lower Circuit Problems

Problem
Gear pump (P1) is noisy (cavitation).
Cutting units will not lift or lift slowly.
Cutting units raise, but will not stay up.
Greensmaster 3120
17230SL Rev C
Hydraulic tank fluid level is low (other hydraulic circuits
affected as well).
Hydraulic pump suction line is restricted.
Hydraulic pump suction line has an air leak.
Engine speed is too low.
Hydraulic tank fluid level is low.
Lift cylinder linkage is binding or broken.
Lift cylinder bushings are binding or worn.
Charge circuit pressure is low; refer to Charge Relief Valve
Pressure Test in the Testing section of this chapter.
Lift circuit relief valve (in steering control valve) is leaking
or damaged.
Mower manifold solenoid valve (S2) is leaking or damaged
(not shifting to its energized position).
An electrical problem exists with solenoid valve S2 (see
Chapter 5 – Electrical System).
Relief valve (R2) is leaking or damaged.
The lift cylinder(s) is leaking internally.
Spool in steering control valve is sticking; refer to Steering
Control Valve Test in the Testing section of this chapter.
Gear pump (P1) is damaged; refer to Gear Pump (P1) Flow
Test in the Testing section of this chapter.
Mower manifold solenoid valve (S4) leaks or is damaged.
The lift cylinder(s) is leaking internally.
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Possible Causes
Hydraulic System: Troubleshooting