Textron JACOBSEN GP400, Technical/Repair Manual

Page: 167 / 354

HYDROSTATIC POWER TRAIN
4252490-Rev A 5-49
5
1. Park the mower safely. (See “Park Mower Safely” on
page 1-6.)
2. Before performing this test, perform wheel motors
tests leaving flow meter and rear wheel restraint
connected as outlined. (See “Wheel Motors Tests”
on page 5-43.)
3. Remove blocking disk at location (3). See
Figure 5-44. Connect tee fitting back to flushing
valve.
4. Open flow meter valve completely before starting
engine.
Figure 5-46: Flushing Valve Check Valve Test—3WD
Models—Rear Wheel Restrained
NOTE
Verify engine rpm is within specification (3400 rpm ± 50)
to ensure accurate hydraulic test results.
5. Start engine, release park brake, and run at full
throttle (3400 rpm ± 50).
Figure 5-47
6. Adjust flow lock tool (1) to allow pump to produce 7
gpm (27 lpm) in the forward direction.
7. Use the flow meter to warm the hydraulic oil. Turn
flow meter valve until a reading of 1000 psi (69 bar)
is reached. Warm the oil to 120–150° F (49–65° C);
open valve fully after operating temperature is
reached.
8. After warming the hydraulic oil, verify flow lock tool is
adjusted to allow pump to produce 7 gpm (27 lpm) in
the forward direction.
9. Slowly close flow meter valve until a reading of
2500 psi (172 bar) is reached. Read and record
loaded flow.
10. Stop engine, apply park brake, and return flow lock
tool to the neutral position.
11. Calculate check valve leakage.
(Step 37 of previous test – Step 9 / Step 37 of
previous test x 100 = Leak Percentage)
Is check valve leakage 10% or less?
YES The check valve is good. Proceed to step 12.
NO Proceed to next question.
Is check valve leakage 11–20%?
YES The check valve is marginal. Additional
testing is required. Proceed to step 12.
NO Proceed to next question.
Is check valve leakage 21% or more?
YES Repair or replace check valve. See “Flushing
Valve” on page 5-55, then proceed to
step 12.
12. Disconnect and remove test equipment. Install all
hoses and fittings as noted prior to removal.
13. Check hydraulic oil level and add if necessary. (Refer
to “Parts and Maintenance Manual” for correct oil
specifications.).
TN4032
1
TN3947