Moog D651 Série Mode D'emploi page 4

9 Maintenance
Except for a regular visual inspection for exterior leakage and
filter change, no maintenance work on the valves is required.
Changing the filter: The installed filter protects internal ori-
fices and nozzles against coarse particle contamination. The
valve response time will increase as contamination increases.
The filters located below the filter cover at the side may be re-
placed by the customer.
NOTICE
Changing the filter
Cleaning serves no purpose.
NOTICE
Fluid flow through the filter disk (2) is from inside to outside
leaving particles behind the filter disk (2) and cannot be seen
from the outside after removing the filter cover (4).
NOTICE
 Before beginning work, clean the outside of the valve
around the filter cover!
• Remove hexagon socket screws (5) with a wrench and
remove the filter cover (4). Remove the filter disk (2),
which is now accessible, with tweezers or a fine screw-
driver.
1
2
3
4
Fig.: Principles of construction
• Check O-rings (1) and (3) and replace if necessary.
• Install new filter disk. To do this, first insert the O-Ring
(1), then the filter disk (2) so that the side of the filter disk
with the indentation faces the outside. Insert O-ring (3) in
the filter cover (4) with some clean grease and mount.
• Cross-torque screws to:
Type Series
pQ-Proportional D651 / D656
Valve / D691
• After start-up, check valve for external leakage.
Replacing O rings: The mounting surface O rings may be re-
placed by the customer (on the pilot valves and the way valves
as well). Pay attention to cleanliness of the valve and of the
surroundings.
Transportation/storage: Before transportation, seal the base
of the valve using a clean shipping plate or adhesive tape.
Seal the connector using a dust protection cap. Pack the valve
carefully so that it is not damaged during transportation or stor-
age.
Inspection: Following a period of storage or no operation for
more than 5 years, we recommend that the valve is inspected
by an authorized service center, in order to prevent possible
damage.
Repairs: Repairs may only be carried out by us or by our au-
thorized service centers.
Mounting and Installation Notes D651, D656/7/8, D691/2/3/4 (B97072-651-001; Version G, 02/15)
5
Torque
Screw [Nm] (lbf in)
M4 x 12–10.9 4.00 (35.4)
10 Disposal
It is essential to comply with the relevant national waste dis-
posal regulations and environmental protection provisions
when disposing of valves, spare parts or accessories, packag-
ing that is no longer needed, hydraulic fluid or auxiliary materi-
als and substances used for cleaning!
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