Textron JACOBSEN GP400, Technical/Repair Manual

Page: 231 / 354

HYDRAULICS
4252490-Rev A 6-39
6
NOTE
Verify engine rpm is within specification (3400 rpm ± 50)
to ensure accurate hydraulic test results.
25. Start engine and run at full throttle (3400 rpm ± 50).
26. Use the flow meter to warm the hydraulic oil. Turn
flow meter valve until a reading of 1500 psi (103 bar)
or 50% of the relief valve rating is reached. Warm oil
to 120–150° F (49–65° C); open valve fully after
operating temperature is reached.
27. Engage mow switch.
28. Slowly close flow meter valve until pressure reaches
2200 psi (152 bar) or 75% of the relief valve rating is
reached. Read and record the center reel motor
loaded flow.
29. Open flow meter valve, disengage mow switch, and
stop engine.
30. Calculate center reel motor leakage.
(Step 19 – Step 28 / Step 19 x 100 = Leak
Percentage)
Is center reel motor leakage 10% or less?
YES The center reel motor is good. Proceed to
step 31.
NO Proceed to next question.
Is center reel motor leakage 11–20%?
YES The center reel motor is marginal. Determine
component(s) with greatest leakage and
repair or replace as necessary, then proceed
to step 31.
NO Proceed to next question.
Is center reel motor leakage 21% or more?
YES Repair or replace center reel motor. See
“Reel Motor” on page 8-28, then proceed to
step 31.
31. Remove blocking device or tool from center reel
motor.
32. Disconnect and remove test equipment. Install all
hoses, lines, and fittings as noted prior to removal.
33. Install and connect all components as noted prior to
test.
34. Check hydraulic oil level. Add oil as needed. (Refer
to “Parts and Maintenance Manual” for correct oil
specifications.)
Implement Relief Valve Pressure Test
See Figures 6-35 through 6-37.
NOTE
Before performing this test, perform field test procedures.
(See “Field Test Procedures” on page 6-28.)
!
WARNING
1. Operate hydraulic system until oil temperature is
120–150° F (49–65° C).
2. Park the mower safely. (See “Park Mower Safely” on
page 1-6.)
Figure 6-35
3. Disconnect hose (2) from traction pump port “V1” (1).
The hydraulic system is under pressure, and the
oil will be hot.
• Always relieve pressure in the hydraulic
system before performing service.
• Failure to follow appropriate safety
precautions may result in death or serious
injury.
Required Tools and Materials
• Pressure Gauge 2000 psi (138 bar)
• Test Hose 2000 psi (138 bar)
• -6 ORFS Tee Fitting
1
TN3978
2