DISTRIBUTION SYSTEMS - PRIMARY HYDRAULIC POWER SYSTEM
Relief valve - Flow test (A.10.A.16 - F.40.A.45)
435, 445, 445CT
1. Park the machine on a level surface. Lower the
loader bucket to the floor. Stop the engine.
2. Disconnect the hos e from th e fitting on the pressure
port of the hy
draulic pump. Install a T fitting at the
pressure port on the hydraulic pump. Reconnect the
pressure hose to one side of the T fitting. Connect
the flowmeter
inlet hose to the remaining connection
on the T fi tting. Place the flowmeter outlet
3. Make sure that the oil level in the hydraulic reservoir
is correct.
4. The oil must be at operating temperature. If the oil
is not at operating temperature, run the engine at
full throttle. Hold the au x iliary hy draulic flow control
pedal in the ON position and close the pressure
valve of the flowmeter until the pressure gauge
indicates 103 bar (1500 psi). Continue to run the
engine at full throttle until the temperature of the oil
is 52°C (125°F).
5. Continue to ho ld th e auxiliary hyd raulic flow control
pedal in the ON position. Continue to run the
engine at full throttle. Slowly close the pressure
valve. As the pressure increases, the flow indication
will decrease slowly. As you continue to close the
pressure valve , you will reach a poin t at which the
flow indication begins to decrease rapidly. This is
the point at which the main relief valve starts to
open. Read the pressure gauge and record the
reading as test number 5.
6. Continue to close the pressure valve until the
indication of the flow gauge is zero. This is the point
at which the main relief valv e is com p letely open.
Read the pressure gauge and record the reading
as test numb er 6.
7. Open the pressure valve completely. De c re ase the
engine speed to low idle and stop the engine.
8. Re
fer to specifications Relief valve - General
specification (A.10.A.16 - D.40.A.10) If the
pressure setting of the main relief valve is not within
t
he specifications, try to adjust the main relief valve.
If the main relief valve cannot be adjusted to the
correct setting, you must replace the main relief
v
alve.
9. If you adjusted, repaired, or replaced the main relief
valve, repeat steps 5 through 7.
10. If the completely open pressure (step 6) is as
specified, but the pressure at which the main relief
valve begins to open (step 5) is 183 bar (2400 psi)
or less, the main relief valve is damaged and must
be replaced before you do further testing.
NOTE: Understanding the results of the tests are outlined
in the steps below.
1 04/05/2005
A.10.A / 27
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