TM 5-3805-260-24
1 Move the control lever to the respective OPERATE
position.
2. Get the engine to test rpm.
3. Make an adjustment to the manual load valve to get
1000 psi pressure.
4. Keep the system constant with these conditions.
5. Write down the flow rate (gpm) for each test.
The flow differential for each test (15, 16, and
17) is found by:
Subtract the flow rate (gpm) for each test from
its respective base flow rate (12 minus 15, 13 minus 16,
and 14 minus 17).
The percent of flow loss for each test 15, 16, and
17 is found by:
Divide the flow differential by its respective base
flow rate and multiply by 100.
Test 20: System Oil Temperature
1. Open the manual load valve fully.
2. Move the elevator control lever to the FORWARD
SLOW position.
3. Write down the oil temperature.
Make a comparison of the oil temperature from
Test 11 and 20. Test 11 must be 150 5 F and Test 20
must be inside of (within) 10 F of Test 11. For each 10
F higher difference, subtract . 5 gallon per pump
cartridge from the leakage rate. For each 10 F lower
difference, add . 5 gallon per pump cartridge to the
leakage rate.
Test 21: Bowl Circuit Drift Comparison
Test 21 is a comparison of visual drift rates for
the bowl circuit. This test is used to check the condition
of the carry check valves. Raise the bowl approximately
one foot off the ground. Turn the manual load valve all
the way out for minimum restriction. Stop the engine.
With the bowl control lever in the HOLD position,
look for a down drift (movement) in the bowl. Then move
the control lever to the RAISE position. Look for down
drift again. If the drift in the RAISE position is more than
the drift in the HOLD position, put a circle around the M
in
the
Test Data box. If the drift in the RAISE position is the
same or less than the drift in the HOLD position, put a
circle around the S in the Test Data box.
"Is It Necessary to Make More Tests?
If So, Which Circuit(s)?"
Make a comparison of the test data on Charts A
and B for the specific machine under test. The percent
of flow loss on Charts A and B is the maximum for best
performance.
Components that are worn, or do not work
correctly, are found by their flow differential and percent
of flow loss or lower system efficiency. System values
for new and rebuilt machines must not be more than the
percent of flow loss in the system tests shown on Chart
A or B for the specific machine. The permissible flow
differential is a function of machine application. If the
flow loss is acceptable, the Tee Test is complete.
If the flow loss is not acceptable in one or more
systems, the tests for the pump and/or the blocked
circuits must be done.
If the flow loss is not acceptable in only one of
the circuits, do the tests for that circuit as shown on the
insert pages. The leakage rate of any component in a
circuit is found by:
Subtract the test information with the compo-
nent in the circuit from the test information with the
component out of the circuit.
Troubleshooting
The examples that follow are a list of problems
and probable reasons. They will give aid to find the
location of the components that are worn, or do not work
correctly. Not all probable reasons have an application
to all machines.
PROBLEM: Setting for the main relief valve is higher
or lower than given in Test 1. Percent of
flow loss for Tests 4 through 7 is 15% to
50%.
PROBABLE REASON:
Setting for main relief valve is not correct and
leakage is too high.
RECOMMENDATION FOR ACTION:
Make adjustments to the main relief valve to get
the correct pressure. Make a test for leakage in the
problems that follow.
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