Textron JACOBSEN GP400, Technical/Repair Manual

Page: 228 / 354

6-36 4252490-Rev A
HYDRAULICS
6
Figure 6-30: Reel Valve Unit Test—Blocking Disk at
Right Reel Motor
5. Block each side of rear wheels using suitable wheel
blocks.
6. Bypass seat switch and release park brake.
NOTE
Verify engine rpm is within specification (3400 rpm ± 50)
to ensure accurate hydraulic test results.
7. Start engine and run at full throttle (3400 rpm ± 50).
!
CAUTION
8. 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.
9. Engage mow switch.
10. 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 front reel valve unit
loaded flow.
11. Open flow meter valve, disengage mow switch, and
stop engine.
12. Calculate reel valve unit leakage.
(Step 10 of previous test – Step 10 / Step 10 of
previous test x 100 = Leak Percentage)
Is reel valve unit leakage 10% or less?
YES The reel valve unit is good. Proceed to
step 13.
NO Proceed to next question.
Is reel valve unit leakage 11–20%?
YES The reel valve unit is marginal. Additional
testing is required. Proceed to step 13.
NO Proceed to next question.
Is reel valve unit leakage 21% or more?
YES Repair or replace reel valve unit. See “Reel
Valve Unit” on page 6-48, then proceed to
step 13.
13. (See Figure 6-28.) Disconnect hydraulic hose at
fitting (1) on right reel motor and remove blocking
disk.
14. Reconnect hydraulic hose to right reel motor.
15. Proceed to “Reel Motors Test” on page 6-36.
Reel Motors Test
See Figures 6-31 through 6-34.
IMPORTANT
• Performing this test will isolate the reel motors
from the rest of the cutting units circuit.
• This test works together with the cutting units
circuit test, gear pump test, and reel valve unit
test to isolate a problem with the cutting units
circuit.
!
WARNING
Do not exceed 3020 psi (208 bar) as this test does
not utilize system relief and damage may occur to
hydraulic system components.
TN3099
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
• Flow Meter
• -8 ORFS Test Hose 4000 psi (276 bar)
• -8 ORFS Tee Fitting
• Blocking Device or Tool