Toro Groundsmaster 4500-D Service Manual page 71

Procedure for Cutting Deck Gear Pump Flow Test
NOTE: Over a period of time, the gears and wear plates
in the pump can wear. A worn pump will by pass oil and
make the pump less efficient. Eventually, enough oil loss
will occur to cause the cutting unit motors to stall under
heavy cutting conditions. Continued operation with a
worn, inefficient pump can generate excessive heat and
cause damage to the seals and other components in the
hydraulic system.
1. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine for approximately 10
minutes. Make sure the hydraulic tank is full.
2. Park machine on a level surface with the cutting units
lowered and off. Make sure engine is off and the parking
brake is engaged.
CAUTION
Prevent personal injury and/or damage to equip-
ment. Read all WARNINGS, CAUTIONS, and Pre-
cautions for Hydraulic Testing at the beginning
of this section.
3. Locate gear pump section to be tested (P1 or P2).
Disconnect appropriate hydraulic hose from 90
draulic fitting in gear pump (Fig. 31).
4. Install hydraulic flow meter in series with the discon-
nected hose and fitting in gear pump section.
5. Make sure the flow control valve on the tester is fully
open.
6. Start engine and move throttle to full speed (2800 +
50 RPM). Do not engage the cutting units.
IMPORTANT: Do not fully restrict oil flow through
tester. In this test, the flow tester is positioned be-
fore the relief valve. Pump damage can occur if the
oil flow is fully restricted.
7. Watch pressure gauge carefully while slowly closing
the flow control valve until 2000 PSI is obtained. Verify
with a phototac that the engine speed is 2800 + 50
RPM.
Groundsmaster 4500--D/4700--D
8. Flow indication should be approximately 11.5 GPM.
9. Shut off engine.
10.Disconnect flow tester from hydraulic hose and fit-
ting. Reconnect hose to the fitting.
11. If flow was less than 11.5 GPM or a pressure of 2000
PSI cannot be obtained, check for restriction in the pump
intake line (including oil filter and oil cooler). If line is not
restricted, remove gear pump and repair or replace as
necessary.
2
o
hy-
1. Gear pump
o
2. 90 hydraulic fitting
Page 4 - - 33
3
4
1
Figure 31
3. Pump section P1 hose
4. Pump section P2 hose
Hydraulic System (Rev. A)