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Groundsmaster 3505--D Hydraulic SystemPage 4 -- 29
Procedure for Charge Relief Valve Pressure
Test:
1. Make sure hydraulic oil is at normal operating tem-
perature.
2. Park machine on a levelsurface with the cuttingunits
lowered and off. Make sure engine is off and the parking
brake is engaged.
3. Read Precautions for Hydraulic Testing.
WARNING
Before disconnecting or performing any work
on the hydraulic system, all pressure in the
system must be relieved. See Relieving Hy-
draulic System Pressure in the General Infor -
mation section.
4. Disconnect hose to the rear 90
o
hydraulic fitting on
the pistonpump coming from the hydraulic manifoldport
(CHG). Connect T --connector and hydraulic pressure
gauge to the fitting and hose connection.
5. Make sure that traction pedal is in neutral and the
parking brake is engaged.
6. Start engine and operate engine at full speed (3050
+
50 RPM).
7. Pressure gauge should read from 100 to 150 PSI.
Record test result.
8. If chargerelief pressure specification is not met,con-
sider the following:
A. The piston pump charge relief valve is faulty. Re-
pair or replace the piston pump charge relief valve
(see PistonPump Servicein theService and Repairs
section).
B. Gear pump (P2) is faulty (steering and lift circuits
are also affected).
9. Adynamic chargepressure testcan be performedas
follows:
A. With T--connector and hydraulic pressure gauge
still connected, sit in the operator seat and press the
traction pedal to forward.
B. While machine is moving, monitor the charge
pressure reading on the pressure guage.
C. The charge pressure should drop no more than
15% from initial test reading (Step 7 above) as the
machine is moving. A pressure drop of more than
15% indicates a traction circuit leak (e.g. a worn or
damaged piston pump and/or wheel motor).
NOTE: If charge pressure is good under no load, but
drops below specification when under traction load, the
piston pump and/or wheel motor(s) should be sus-
pected of wear. When a pump and/or motor is worn or
damaged, the charge pump is not able to keep up with
internal leakage in the traction circuit.
10.Stop machine and shut off engine.
11.Relieve hydraulic system pressure (See Relieving
Hydraulic System Pressure in the General Information
section). Disconnect gauge and T--connection from the
90
o
hydraulic fitting and hose connection. Reconnect
hose to the hydrostat.
1. 90
o
hydraulic fitting 2. Piston pump
Figure 17
2
1
Hydraulic
System