Toro Greensmaster 3250-D 04383 Service Manual page 77

Procedure for Charge Relief Valve (R4) Pressure
Test
1. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine for approximately ten
(10) minutes.
2. Park machine on a level surface with the cutting
units lowered. Make sure engine is off and the parking
brake is engaged. Make sure the hydraulic tank is full.
CAUTION
Before continuing further, read and become fa-
miliar with Precautions for Hydraulic Testing.
3. Disconnect hydraulic hose from the fitting in the
charge port of piston pump P3 (traction pump section).
Connect T--fitting and pressure gauge to the fitting and
hose connection.
4. Make sure that traction pedal and lift control are in
neutral and the parking brake is engaged.
5. Start engine and operate at full speed (2750 + 50
RPM).
6. Pressure gauge should read approximately 100 to
150 PSI (6.9 to 10.3 bar). Record test results.
Greensmaster 3250--D
7. Shut off engine.
8. If specification is not met, remove hydrostat back
plate assembly that contains the charge relief valve (see
Piston Pump Service in the Service and Repairs section
of this chapter). Repair or replace relief valve compo-
nents as necessary.
9. A dynamic charge pressure test can be performed
as follows:
A. With tester still connected, sit in the operator
seat, start the engine and release the parking brake.
B. Press the traction pedal to forward.
C. While machine is moving, monitor the charge
pressure reading on the pressure gauge.
D. 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 hydrostat and/or
wheel motor). Further testing of the traction circuit
should be completed (see Traction Drive Hydrostat
(P3) Flow and Wheel Motor Efficiency Tests in this
section).
10. When testing is complete, disconnect pressure
gauge and T--fitting from the pump fitting and hose. Re-
connect hose to the pump fitting.
Page 4 - - 39 Rev. J
Hydraulic System (Rev. I)