Testing The Traction Circuit-Piston Pump/Hydrostat Flow And Relief Pressure - Toro Groundsmaster 4300-D Service Manual

Testing the Traction Circuit–Piston Pump/Hydrostat Flow and
Relief Pressure
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Groundsmaster ® 4300-D
16226SL Rev C
The hydrostat flow test is the third in a series of tests recommended to determine
the traction circuit performance. This test compares fluid flow at No Load with
fluid flow Under Load. A drop in flow under load of more than 12% indicates an
internal leak or malfunctioning relief valve in the piston pump/hydrostat. The
final traction circuit test is verifying the hydrostat relief valve operation. A worn
hydrostat or malfunctioning relief valve is less efficient. Eventually, enough
fluid bypass will cause the unit to stall under heavy load conditions. Continued
operation can generate excessive heat, cause damage to seals and other
components in the hydraulic system, and affect overall machine performance.
Special Equipment Required:
•
Pressure gauge
•
Flow meter with pressure gauge that has at least a 114 L/minute (30
gallons/minute) capacity.
Figure 59
Page 4–55 Hydraulic System: Testing the Hydraulic System