TM 5-3895-382-24
Pressure Test Tools
Tools Needed
4C-4892
Fittings Group
1
Use the above fittings group for all of the pressure tests that
follow. In some procedures, more than one of the same
pressure gauge is required. It may be necessary to use two
pressure gauge kits.
Flushing Valve Charge Relief Valve Pressure Test
Make
reference
to
WARNING
on
first
page
of
Troubleshooting.
NOTE:
The procedure described in this test will measure
charge pressure when the propel control lever is
in the STOP position and the vibration system is
off. This charge pressure is measured and
recorded at the flushing valve.
Flushing valve
(1) Charge pressure test port (2) Charge relief valve. (3) Adjustment
screw. (4) Locknut.
1.
Connect a 0 to 4000 kPa (580 psi) pressure gauge to
charge pressure test port (1) on the flushing valve.
2.
Engage the parking brake. Put the propel control lever
in the STOP position. Start and run the engine at high
idle until the hydraulic oil temperature reaches 38°C
(100°F). Engine rpm should be 2350 ± 50 rpm.
3.
With the propel system in neutral and the vibratory
system off, record the pressure on the gauge connected
to the test port. The charge relief valve setting should
be 1725 ± 69 kPa (250 ± 10 psi).
4.
Charge pressure is determined by pump speed
(steering output), internal leakage of the closed loops,
orifices in the charge reliefs (one vibratory and one
propel) and open centered flushing valve. If the orifices
are ok, the valve must be adjusted. Stop the engine
and proceed to Step 5. If the charge relief valve
pressure is correct, remove all tooling and connect all
hoses.
5.
Install a tachometer on the engine to measure engine
speed. Check to be sure the hydraulic oil temperature
reaches 38°C (100°F).
6.
Loosen locknut (4). Use an allen wrench to turn
adjustment screw (3) clockwise to increase the pressure
or counterclockwise to decrease the pressure. After the
relief valve pressure is adjusted correctly, use an allen
wrench to hold the adjustment screw and tighten the
locknut to a torque of 16 Nm (12 lb-ft).
7.
Verify the charge relief valve pressure. When the
pressure is correct, remove the pressure gauge from the
test port.
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