Service Manual

HYDROSTATIC DRIVE SYSTEM
6-30 Floating Deck Mid-Size Service Manual
6
8. Position a drain pan under the wheel motor.
9. Disconnect both hydraulic hoses from the wheel
motor (Fig. 1042).
12. Open the restriction valve all the way (counterclock-
wise) (Fig. 1044).
Fig 1042 PICT-0379
Fig 1044 PICT-6886a
10. Cap the wheel motor fi ttings so debris does not enter
the system.
11. Attach the hydraulic hoses to the fl ow test gauge
(Fig. 1043).
Note: When using a fl ow test gauge that is not bi-
directional, damage to the fl ow tester could
occur if the machine is operated in reverse.
Fig 1043 PICT-6885
13. Run the machine for 2 minutes in forward (no load)
to purge air from the system.
14. Run the machine at full throttle (no load). Verify the
RPM with a tachometer: 3200 + 150 RPM’s. Do not
exceed 3600 RPM.
15. With the drive control fully forward, slowly tighten the
restriction valve until the gauge indicates 300 PSI
(21 bar).
16. Record the fl ow reading from the bi-directional fl ow
meter. Refer to the Hydro-Gear manual for accept-
able GPM. Make a second fl ow reading at 1100 PSI
(76 bar) and record that reading. Subtract the fi rst
reading from the second reading and determine if it
is an acceptable GPM.
Example:
1st Reading: 300 psi (21 bar) reading 7 gpm (26 l/m).
2nd Reading: 1100 psi (76 bar) reading 3 gpm (11 l/m).
7 gpm (1st reading)
- 3 gpm (2nd reading)
4 gpm (the difference)
An acceptable “fl ow droop” or difference is 1.5 gpm
(5.6 l/m)