Toro Groundsmaster 4100-D Service Manual page 83

Procedure for Steering and Lift/Lower Gear Pump
Flow Test
Output from the steering and lift/lower gear pump sec-
tion is equally divided by a proportional valve to provide
flow to the steering circuit and the lift circuit. To test gear
pump flow, testing of both steering and lift/lower circuits
is required. Total gear pump flow is the combined flow
from the two circuits.
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
decks lowered and off. Make sure engine is off and the
parking brake is engaged. Raise seat.
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.
IMPORTANT: Make sure that the oil flow indicator
arrow on the flow gauge is showing that the oil will
flow from the pump, through the tester, and into the
hydraulic hose.
3. With the engine off and cutting decks lowered, install
tester with pressure gauges and flow meter in series be-
tween the last gear pump section and one of the circuit
hoses (Fig. 34). Make sure the tester flow control
valve is open.
4. After installing tester, start engine and run at idle
speed. Check for hydraulic leakage and correct before
proceeding with test.
IMPORTANT: The pump is a positive displacement
type. If pump flow is completely restricted or
stopped, damage to the pump, tester, or other com-
ponents could occur.
5. Operate the engine at full speed (2730 + 30 RPM).
DO NOT engage the cutting decks.
6. While watching tester pressure gauges, slowly close
flow control valve on the tester until 1000 PSI is obtained
on gauge. Verify engine speed continues to be correct
(2730 + 30 RPM). Record test results.
GAUGE READING TO BE: Flow approximately 3.5
GPM at 1000 PSI.
7. Open tester flow control valve and stop engine. Re-
move tester and reinstall disconnected hose. Complete
steps 3 through 6 for other circuit hose.
Groundsmaster 4100--D
8. If the total of the two flows is lower than 7 GPM or a
pressure of 1000 PSI could not be obtained, check for
restriction in pump intake line. If intake line is not re-
stricted, remove gear pump and repair or replace as
necessary.
If the total of the two flows is 7 GPM but individual circuit
flow is less than 3.5 GPM (e.g. steering circuit has 2
GPM and lift circuit has 5 GPM), suspect a problem with
the proportional valve in the gear pump.
1
1. Hydraulic tank cap
2. Lift circuit hose
1
1. Gear pump backplate
2. Lift circuit
Page 4 - - 41
2
3
Figure 34
3. Steering circuit hose
2
3
4
Figure 35
3. Steering circuit
4. Proportional valve
Hydraulic System