Toro Groundsmaster 3500 30807 Service Manual page 115

Cutting Deck Circuit Testing − Gear Pump (P1) Flow
Test:
The gear pump (P1) flow test is the last in a series of
tests recommended to determine cutting deck circuit
performance. This test compares fluid flow at No Load
with fluid flow Under Load. A drop in flow under load of
more than 15% indicates the gears and wear plates in
the pump have worn. A worn pump will by−pass hydraul-
ic fluid and make the pump less efficient. Eventually,
enough fluid loss will occur to cause the cutting unit mo-
tors to stall under heavy cutting conditions. Continued
operation with a worn, inefficient pump can generate ex-
cessive heat and cause damage to the seals and other
components in the hydraulic system.
Special Equipment Required:
S Flow Meter with Pressure Gauge that has at least
a 12 GPM (45 LPM) capacity.
S Phototach (non−contact tachometer).
1. Park machine on a level surface with the cutting units
lowered and PTO switch off. Make sure engine is off and
the parking brake is engaged.
2. Read Precautions for Hydraulic Testing in this
chapter.
3. Disconnect hose connection on the gear pump (P1)
leading to port (P1) on the hydraulic manifold (Fig. 37).
4. Install tester between the gear pump and the discon-
nected hose.
5. Make sure the flow control valve on the tester is fully
open.
6. Sit in the Operator's seat, start the engine, and move
throttle to full speed (Diesel engine = 3220 + 50 RPM,
Gas engine = 3420 + 30 RPM). Do not engage the cut-
ting units.
7. Make sure hydraulic fluid is at normal operating tem-
perature by operating the machine for approximately 10
minutes.
Use a phototach to verify that the pump speed is ap-
proximately 2850 RPM.
8. Verify pump flow at No Load as follows:
Record tester pressure and flow reading at no load.
Unrestricted pump output should be approximately
11.1 GPM (42.1 LPM).
Groundsmaster 3500
2
RIGHT
FRONT
1. Gear pump assembly
9. Verify pump flow Under Load as follows:
Do not close tester valve fully when perform-
ing this test. In this test, the hydraulic tester is
positioned before the manifold relief valve.
Pump damage can occur if the fluid flow is fully
restricted by fully closing the tester flow con-
trol valve.
A. Watch flow meter pressure gauge carefully while
slowly closing the flow control valve until 2000 PSI
(137.9 Bar) is obtained on gauge.
B. Record tester pressure and flow readings under
load.
10.Set throttle to low speed and shut off engine.
11. The under load test flow reading (step 9.B) should
not drop more than 15% when compared to no load test
flow reading (step 8.A). A difference in flow of more than
15%, or the inability to achieve specified pressure may
indicate:
A. A restriction in the pump intake line
B. A Worn and/or slipping traction belt
C. The gear pump (P1) is worn and should be re-
paired or replaced
12.Disconnect tester and reconnect hose to pump.
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1
P2
P1
Figure 37
2. To hydraulic manifold
CAUTION
Hydraulic System