Toro 30821 Service Manual page 77

Procedure for Charge Relief Valve Pressure Test:
1. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine for approximately 10
minutes.
2. Park machine on a level surface with the cutting units
lowered and off. Make sure engine is off and the parking
brake is engaged.
3. Read Precautions for Hydraulic Testing.
4. Disconnect hose to the rear 90
the piston pump coming from the hydraulic manifold port
(CHG). Connect T- connector and pressure gauge to
the fitting and hose connection.
5. Make sure that traction pedal is in neutral and the
parking brake is engaged.
6. Start engine and operate engine at full speed (3050
+ 50 RPM).
7. Pressure gauge should read from 100 to 150 PSI.
8. If charge relief pressure specification is not met, con-
sider the following:
A. The piston pump charge relief valve is faulty. Re-
pair or replace the piston pump charge relief valve
(see Piston Pump Service in the Service and Repairs
section).
B. Gear pump (P2) is faulty (steering and lift circuits
are also affected).
9. A dynamic charge pressure test can be performed as
follows:
A. With T- connector and pressure gauge still con-
nected, sit in the operator seat and press the traction
pedal to forward.
B. While machine is moving, monitor the charge
pressure reading on the pressure guage.
C. The charge pressure should drop no more than
15% from initial test reading (Step 7 above). A pres-
sure drop of more than 15% indicates a traction cir-
cuit leak (e.g. a worn or damaged piston pump
and/or wheel motor).
10.Shut off engine.
11. Disconnect gauge and T- connection from the 90
hydraulic fitting and hose connection. Reconnect hose
to the hydrostat.
Groundsmaster 3500- D
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hydraulic fitting on
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1
Figure 55
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1. 90 hydraulic fitting
Hydraulic System (Rev. G)
2
2. Piston pump