HYDRAULICS
4181383 First Edition 6-35
6
IMPORTANT
• If performing this test after performing rear
cutting units circuit test and test proved rear
cutting units pump, deck valve, and left rear
cutting unit motor good, proceed to step 14.
• If performing this test to determine which
component in system is at fault (left rear cutting
unit motor, center cutting unit motor, or right rear
cutting unit motor) continue to step 4.
!
WARNING
4. Install suitable blocking device or tool in left rear
cutting unit, preventing cutting unit from turning.
Figure 6-29
5. Open flow meter valve (3) completely.
NOTE
Verify engine rpm is within specification (2850 rpm ± 50)
to ensure accurate hydraulic test results.
6. Start engine and run at full throttle (2850 rpm ± 50).
7. Use the flow meter to warm the hydraulic oil. Turn the
flow meter valve (3) until a reading of 1300 psi (90
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.
8. Disconnect park brake switch.
9. Engage cutting unit switch.
10. Slowly close flow meter valve (3) until pressure
reaches 1950 psi (134 bar). Read and record the left
rear cutting unit motor loaded flow.
11. Open flow meter valve (3) and stop engine.
12. Calculate left rear cutting unit motor leakage.
(Step 10 of rear cutting units circuit valve tests –
Step 10 / Step 10 of rear cutting units circuit valve
tests x 100 = Leak Percentage)
Is left rear cutting unit motor leakage 10% or
less?
YES The left rear cutting unit motor is good.
Proceed to step 13.
NO Proceed to next question.
Is left rear cutting unit motor leakage 11% to
20%?
YES The left rear cutting unit motor is marginal.
Additional testing is required.
NO Proceed to next question.
Is left rear cutting unit motor leakage 21% or
more?
YES Repair or replace left rear cutting unit motor.
(See “Cutting Unit Motors” on page 6-43.)
13. Remove device or tool from left rear cutting unit.
!
WARNING
14. Install suitable blocking device or tool in center
cutting unit, preventing cutting unit from turning.
15. Open flow meter valve (3) completely.
16. Connect park brake switch.
NOTE
Verify engine rpm is within specification (2850 rpm ± 50)
to ensure accurate hydraulic test results.
17. Start engine and run at full throttle (2850 rpm ± 50).
18. Use the flow meter to warm the hydraulic oil. Turn the
flow meter valve (3) until a reading of 1300 psi (90
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.
19. Disconnect park brake switch.
20. Engage cutting unit switch.
21. Slowly close flow meter valve (3) until pressure
reaches 1950 psi (134 bar). Read and record the
center cutting unit motor loaded flow.
22. Open flow meter valve (3) and stop engine.
Safely block cutting unit from rotating using a
suitable device or tool. Failure to follow
appropriate safety precaution may result in death
or serious injury.
TN1363
3
Safely block cutting unit from rotating using a
suitable device or tool. Failure to follow
appropriate safety precaution may result in death
or serious injury.
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