Toro Groundsmaster 4300-D Service Manual page 110

Test Procedure (continued)
Hydraulic System: Testing the Hydraulic System
8. Attach a heavy chain to the rear of the machine frame and an immovable
object to prevent the machine from moving during testing.
9. Block the wheels with chocks to prevent the wheel rotation during testing.
10. Start the engine and press the engine speed switch to full speed (3,005 to
3,055 rpm) position. Use the InfoCenter to check that the engine speed is
correct.
11. Record the reading on the charge circuit pressure gauge. The charge
pressure (without load) should read from 1,034 to 1,379 kPa (150 to 200 psi).
If the charge relief pressure specification is not met, consider the following:
A. The gear pump (P3) is damaged (steering circuit performance will also
be affected). Test the gear pump (P3) flow; refer to
Circuit–Gear Pump (P3) Flow (page
B. The piston pump charge relief valve is damaged. Repair or replace the
piston pump charge relief valve; refer to
Pump (page 4–106).
12. Sit in the operator's seat, release the parking brake, and slowly press the
traction pedal forward until 6,900 to 10,340 kPa (1,000 to 1,500 psi) is
reached on the traction circuit pressure gauge.
13. Record the reading on the pressure gauge (under load). The charge
pressure (under load) should not drop more than 20% when compared to
charge pressure (without load) recorded in step 11.
If specifications are not met, perform the piston pump/hydrostat flow and
traction relief pressure test; refer to
Pump/Hydrostat Flow and Relief Pressure (page
14. Release the traction pedal, press the engine speed switch to low speed
position, and shut off the engine.
15. After you complete the charge pressure testing, ensure that the engine is
not running and then release hydraulic system pressure; refer to
Pressure from the Hydraulic System (page
gauges from the test ports.
16. Lower and secure the operator seat.
17. Start the engine, check for hydraulic-fluid leaks, repair any leaks as required,
and fill the hydraulic tank with the correct quantity of new hydraulic fluid
before returning the machine to service.
4–75).
Testing the Traction Circuit–Piston
Page 4–48
Testing the Steering
Servicing the Piston (Traction)
4–55).
Releasing
4–6). Disconnect the pressure
Groundsmaster
16226SL Rev C
® 4300-D