Enerpac VM43-LPS Instrucciones De Mantenimiento página 8

TROUBLESHOOTING AND REPAIR OF VM43-LPS AND VM43-LPSV MANUAL VALVES
In diagnosing malfunctioning valves, certain symptoms may be
common not only to valves, but often to hydraulic equipment in
general. Before repairing the valve, mount a different VM43 valve
onto the pump and verify that the problem is not with the pump.
TROUBLESHOOTING:
CAUTION: Standard safety procedures are to be
followed during assembly to minimize any possibility
of injury.
1. Inability to obtain any pressure may be the result of
damaged connector seals on the pump, or failed relief valve
components (items 6, 7, fi gure 7) a damaged seat (item 57,
fi gure 6), or damaged or worn shear seals and disc (item
80, 84, fi gure 3). These problems are usually a symptom of
contaminated hydraulic oil. The system should be drained
and refi lled with fresh ENERPAC hydraulic oil.
2. Pressure leaks that
proportionately with increasing pressure ranges are usually
the result of leaking gaskets or threaded surfaces such as
NTPF fi ttings or plugs.
3. Ball seat leakage is often erratic and intermittent and is
caused by contaminants trapped on the sealing edge. Over
time, as wear occurs, these seats will need to be replaced.
4. Leakage observed on the external surfaces around the shaft
(item 88, fi gure 3) is an indication that the o-ring (item 90)
and backup ring (item 89) need replacement.
5. Leakage observed on the external surfaces around the relief
valve body (item 1, fi gure 7) is an indication that the o-ring
(item 8) needs to be replaced.
DISASSEMBLY:
1. Remove the 4 socket head cap screws securing the valve
assembly to the pump. Remove the assembly from the
pump.
2. Remove the return tube and gasket (not shown).
3. Remove the screw (item 72, fi gure 3) and washer (item 71)
from the shaft (item 88).
4. Remove handle cap (item 66) lever (item 67) and knob (item
68) as an assembly. Remove ball (item 69) and spring (item
70).
5. Remove the 4 socket head cap screws (item 62, fi gure 1)
and remove the upper valve assembly (item 51) from the
locking block (item 50).
6. Remove the 2 socket head cap screws (item 82, fi gure 3)
and separate the body (item 95) from the valve cap (item
94).
7. Remove the shaft assembly and inspect the o-ring (item 90)
and backup ring (item 89) for damage. Replace if needed.
8. Remove the o-ring (item 93) and inspect for damage such as
nicks or cuts. Replace if needed.
9. Remove the bearing (item 92) and bearing plate (item 91)
and inspect for damage. Replace if needed.
10. Remove the shear seal assemblies (item 84-86) from the
bores in the body.
11. Remove the o-rings (item 86) and backup washers (item 85)
and inspect for damage. Replace if needed.
are consistent and increase
12. Remove springs (item 87) and inspect for damage such as
breakage or permanent set. Replace if needed.
13. Disassembly of the manifold is as follows:
14. Loosen lock nut (item 9, fi gure 7) and unscrew the set screw.
(item 2).
15. Using a 7/8" socket, loosen and remove the relief valve
assembly (item 58, fi gure 6) from the body.
16. Remove the seat (item 57) from the body.
17. Inspect the seat for damage such as nicks or dents on the
sharp edge of the internal diameter. Replace if necessary.
18. Inspect the o-ring (item 8, fi gure 7) for damage and replace if
necessary.
19. Inspect the ball (item 7, fi gure 7) and guide (item 6, fi gure 7).
Replace if necessary.
20. Remove nut (item 48, fi gure 6), set screw (item 47), spring
(item 24), guide (item 46) and ball (item 45). Visually inspect
seat (item 44). If damaged, use special tool DT1560-3 to
lightly re-dress the seat. If the seat cannot be re-dressed,
replace manifold (item 52).
21. Remove the pipe plugs (item 53, 54, 55) and clean the body.
Inspect body for damages. Visually inspect check valve (item
100), but do not remove unless worn or damaged.
22. Disassembly of the Locking Power Seat sub-assembly is as
follows:
23. Remove o-rings (item 27, fi gures 4 & 5) and inspect for
damage such as extrusion of material, cuts or cracks.
24. Remove plugs (item 31). Remove and discard gaskets (item
32). Inspect o-rings (item 33) for damage, such as extrusion
of material, cuts or cracks.
25. Remove and discard ball (item 35).
26. Remove spring (item 34) and inspect for damage.
27. Remove seat (item 39 - opposite of ball end) using a magnet.
Inspect for damage.
28. Using a brass punch (or other soft metal or plastic tool)
push out cylinder (item 42), piston pin (item 30) and seat
(item 39 - ball end) and remove these parts from the bore
as an assembly. Be careful not to scratch or damage bore
surfaces.
29. Remove piston pin (item 30) from cylinder (item 42). Inspect
o-ring (item 28) and backup washers (item 29) for damage.
30. Remove o-ring (item 36) and backup washer (item 37) from
seat (item 39 - ball end). Inspect for damage.
31. Remove backup washers (item 40) and o-ring (item 41) from
cylinder (item 42). Inspect for damage.
REASSEMBLY:
Procedure for Manifold assembly
1. Install pipe plugs (item 53, fi gure 6) and torque to 10-12 ft-
lbs [14-16 Nm]. Install pipe plugs (item 54, 55) and torque to
32-39 ft-lbs) [43-53 Nm].
2. Install copper gasket (item 56) onto seat (item 57), with round
edges facing away from the seat.
3. Place seat (item 57) onto the bottom counter bore in the
valve body, with the gasket side down. Note: make sure
that the seat is fi rmly seated and not crooked.
4. Grease o-ring on relief valve assembly (item 58) and insert
into cavity in the valve body.
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