Case 580SR, Service Manual

Page: 648 / 1068

58 SECTION 35 - HYDRAULIC SYSTEM
System pressure relief valve adjustment
After overhaul, the pressure relief valves of the sys-
tem must be tested and adjusted using a suitable
hand pump (1), a 275 bar pressure gauge and a
V. L. Churchill test kit (2).
The hand pump must be attached to inlet port I and
the drain hose to the outlet port T of test block using
suitable 1/2 inch BSP (British Standard Pipe) adap-
tors.
The pressure gauge may be connected to either the
hand pump as shown or to the 3/8 UNF threaded
port G in the test block.
Remove plug and insert valve to be tested into the
appropriate port in the test block as follows:
A. Stabilizer and backhoe relief valves
B. Loader bucket relief valves
C. Unload valve
NOTE: a special removable insert, which is part of
the test block, is installed in the bottom part of the
port used for testing the loader attachment valve. If
difficulty is experienced in screwing the loader valve
into the test block, check that the insert is fully seat-
ed and correctly installed. When correctly installed
the O-ring (3) on the face of the insert should be vis-
ible.
Operate hand pump and record maximum pressure
reading on gauge. Compare pressure values with
previous specifications.
IMPORTANT: before removing the valve from the
test block, release the pressure in the system using
the vent valve on the hand pump.
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