6-32 4203780 First Edition
HYDRAULICS
6
Figure 6-24: Front Cutting Unit Deck Valve Test—
Blocking Disk at Left Front Cutting Unit Motor
NOTE
Verify engine rpm is within specification (2800 rpm ± 50)
to ensure accurate hydraulic test results.
6. Start engine and run at full throttle (2800 rpm ± 50).
7. Use the flow meter to warm the hydraulic oil. Turn the
flow meter valve (2) until a reading of 1500 psi (103
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. Enable front mower deck switch and engage PTO
switch.
9. Slowly close flow meter valve (2) until pressure
reaches 2250 psi (155 bar). Read and record the
front cutting unit deck valve loaded flow.
10. Open flow meter valve (2), disengage switches, and
stop engine.
11. Calculate front cutting unit deck valve leakage.
(Step 10 of previous test – Step 9 / Step 10 of
previous test x 100 = Leak Percentage)
Is front cutting unit deck valve leakage 10% or
less?
YES The front cutting unit deck valve is good.
Proceed to step 12.
NO Proceed to next question.
Is front cutting unit deck valve leakage 11% to
20%?
YES The front cutting unit deck valve is marginal.
Additional testing is required. Proceed to
step 12.
NO Proceed to next question.
Is front cutting unit deck valve leakage 21% or
more?
YES Repair or replace deck valve. (See “Front
Deck Valve” on page 6-66.) Then proceed to
step 12.
!
CAUTION
NOTE
Verify engine rpm is within specification (2800 rpm ± 50)
to ensure accurate hydraulic test results.
12. Start engine and run at full throttle (2800 rpm ± 50).
13. Enable front mower deck switch and engage PTO
switch.
14. Continue to close flow meter valve (2) until zero flow
is obtained. Record cutting unit deck valve system
relief valve pressure.
15. Open flow meter valve (2), disengage switches, stop
engine.
Is cutting unit deck valve system relief valve
pressure 2700 psi (186 bar) to 3300 psi (228 bar)?
YES Cutting unit deck valve system relief valve is
good. Proceed to “Front Cutting Unit Motors
Test” on page 6-34.
NO Adjust cutting unit deck valve system relief
valve pressure.
(See “Adjust Front Cutting
Unit Deck Valve System Relief Valve
Pressure” on page 6-33.)
TN2073
Do not exceed 3350 psi (231 bar) when testing
system relief valve or equipment damage may
occur.
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