Toro Groundsmaster 7210, Service Manual

Page: 95 / 342

Perform the charge relief valve pressure test if you identify a traction circuit
problem. This test determines if the transmission charge relief valve operates
correctly.
Test Procedure
1. Ensure that the hydraulic fluid is at normal operating temperature.
2. Ensure that the traction drive is correctly adjusted for the N
EUTRAL
position.
WARNING
Before disconnecting or doing any work on the hydraulic system,
release all the pressure in the system; refer to
Releasing Pressure
from the Hydraulic System (page 4–11) .
3. Park the machine on a level surface, lower the cutting deck (or implement),
shut off the engine, and set the parking brake.
4. Read all Warning, Cautions, and precautions listed at the beginning of this
section.
5. Clean the transmission area around the charge-pressure test port on the
right side of the transmission.
6. Remove the plug from the charge-pressure test port.
7. Connect a 6,900 kPa (1000 psi) hydraulic-pressure gauge with an attached
hydraulic hose to the transmission charge-pressure port.
8. Ensure that the traction levers are in the N
EUTRAL LOCK
position and the
parking brake is applied.
9. Start the engine and run it at low-idle speed (1,400 rpm) . Check for
hydraulic-fluid leaks from the test connections and correct before continuing
the test.
10. Operate the engine by moving the throttle to full speed (3,000 rpm) . The
pressure gauge reading should read from 480 to 690 kPa (70 to 100 psi) .
Record the test result.
11. If the charge relief pressure specification is not met, consider the following:
A. The transmission charge relief valve is damaged. Repair or replace the
charge-relief valve; refer to Servicing the Transmission (page 4–75) .
B. A transmission traction relief valve or flushing valve is leaking or
damaged; refer to Servicing the Transmission (page 4–75) .
C. The charge pump in the transmission is damaged (the PTO operation
may also be affected); refer to Servicing the Transmission (page 4–75) .
12. Perform a dynamic charge-pressure test by doing the following:
A. With the hydraulic-pressure gauge still connected, sit in the operator seat
and move the traction levers forward.
B. While the machine is moving, monitor the charge pressure reading on
the pressure gauge.
C. The charge pressure should not drop more than 15% from the initial test
reading (Step 10 ) as the machine is moving (e.g., if the initial charge
pressure is 690 kPa (100 psi) , charge pressure while the machine is
moving should be above 590 kPa (85 psi) .
Groundsmaster 7210 Page 4–35 Hydraulic System: Testing the Hydraulic System
16222SL Rev C