Jacobsen AR3, Technical/Repair Manual

Page: 222 / 342

HYDRAULICS
4181384 First Edition 6-31
6
Figure 6-20
5. Install tee fitting (5) to fitting (2).
6. Connect test hose (6) of flow meter inlet and hose (1)
to tee fitting (5).
Figure 6-21
7. Disconnect hose (8) from fitting (7).
8. Connect tee fitting to fitting (7).
9. Connect test hose (3) and hose (8) to tee fitting.
10. Install suitable blocking device or tool in center rear
cutting unit, preventing cutting unit from turning.
Open flow meter valve (4) completely.
NOTE
Verify engine rpm is within specification (3150 rpm ± 50)
to ensure accurate hydraulic test results.
11. Start engine and run at full throttle (3150 rpm ± 50).
12. Use the flow meter to warm the hydraulic oil. Turn the
flow meter valve (4) until a reading of 1525 psi (105
bar) or one half of the relief valve rating is reached.
Warm oil to 120—150°F (49—65°C), open valve fully
after operating temperature is reached.
13. Engage cutting unit switch.
14. Read and record the cutting unit/charge pump no
load flow.
15. Slowly close flow meter valve (4) until pressure
reaches 2300 psi (159 bar). Read and record the
cutting unit/charge pump system test loaded flow.
16. Open flow meter valve (4) and stop engine.
17. Calculate cutting unit system leakage.
(Step 14 – Step 15 / Step 14 x 100 = Leak
Percentage)
Is cutting unit system leakage 10% or less?
YES The cutting unit system is good. Proceed to
step 18.
NO Proceed to next question.
Is cutting unit system leakage 11% to 20%?
YES The cutting unit system is marginal.
Additional testing is required.
NO Proceed to next question.
Is cutting unit system leakage 21% or more?
YES Test individual components in cutting unit
system for leakage.
18. Disconnect and remove test equipment. Remove
blocking device or tool from cutting unit. Install all
hoses and fittings as noted prior to removal.
19. Check hydraulic oil level. Add oil as needed. (Refer to
“Safety, Operation, and Maintenance Manual” for
correct oil specifications.)
Cutting Unit/Charge Pump Test
See Figures 6-22 through 6-24.
!
WARNING
1. Park the mower safely. (See “Park Mower Safely” on
page 1-7.)
5
6
TN1363
4
3
TN1362
7
8
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
• Test Hose 3000 psi (207 bar)
• Tee Fitting
• Blocking Disk