Preventive Maintenance Checks and Services (PMCS) - Continued.
ITEM TO BE
Relief valves used on this crane have
screw-type adjustments. If it is
determined that a relief valve is out
of adjustment, follow this general
adjustment procedure. Install a
4,000 psi (27,579 kPa) gage in the
designated test port locations and
proceed with pressure check and
If MSD-ICE is available, this version
contains a 5,000 psi (34,474 kPa)
pressure transducer. This may be
substituted for the 4,000 psi gage
referenced for checking the
hydraulic circuit pressures. By
attaching the 1219-879 adapter
between the transducer and the
7091272-18 hose, the transducer's
threaded 1/4-inch pipe connection
will adapt to the hose.
4. Remove acorn nut and loosen jam nut.
5. Run engine at full rpm so pump will develop required
6. Operate one plunger of control valve at its extreme
position long enough to get a pressure reading on the
7. Turn adjusting screw clockwise to increase pressure
or counterclockwise to decrease pressure until desired
pressure setting is obtained.
8. Holding adjusting screw, tighten jam nut. Install and
tighten acorn nut.
9. Retest to check pressure setting.
Results of the above settings will indicate a
relatively constant relief valve setting across
full engine rpm.
12. Check steering/swing control relief valve