Service Manual

Mid-Size Walk Behind Service Manual 5 - 25
HYDRAULIC DRIVE SYSTEMS
6. Run the machine for 2 minutes in forward (no
load) to purge air from the system.
7. Run engine at full throttle (no load) - verify RPM
with a tachometer - 3200 + or - 150 RPM's. Do
not exceed 3600 RPM.
8. With the drive control fully forward (Pistol Grip,
Figure 112, T-Bar, Figure 113) slowly tighten the
restriction valve until the gauge indicates 300 PSI
(21 bar).
Figure 112
mvc-896
Record the flow reading from the bi-directional
flow meter. Refer to the Hydro-Gear manual for
acceptable GPM. Make a second flow reading at
1100 PSI and record. Subtract the first reading
from the second reading and determine if this is
an acceptable GPM.
Figure 113
mvc-898
Example:
An acceptable “flow droop” or difference is: 1.5
gpm (5.6 liter/min).
9. When test is complete and if necessary repairs
have been made - reassemble hydraulic lines to
wheel motor and reassemble wheel to hub and
torque wheel nuts to 85 ft. lbs. (115 N-m) + or - 8
ft. lbs.
10. Test operate machine and purge air from hydraulic
system.
Wheel Motor Removal and
Installation - Floating Deck
1. Identify hydraulic lines.
2. Remove hydraulic lines from wheel motor.
3. Unbolt 4 screws holding wheel motor to chassis.
Note: If wheel hub is to be removed, see step 5
on page 5 - 26, Figure 115.
1st Reading 300 psi (21 bar) reading 7 gpm
(26l/min).
2nd Reading 1100 psi (76 bar) reading
3 gpm (11l/min).
300 psi (21 bar) reading
7gpm (26l/min) (1st reading)
- 3gpm (11l/min) (2nd reading)
4 gpm (15l/min) (the difference)
Subtract 1st reading from the
2nd. (In this example, 4gpm
difference would indicate a
defective pump).