Series 766 - O-Ring Replacement

Leakage, broken parts, hard operation, and other defects should be corrected by a repair crew as soon as possible
after the defect has been reported. If repairs are to be performed in the field, the repair crews should take a full complement of spare parts to the jobsite. Provisions should be made to isolate the defective valve from water pressure and relieve internal trapped pressure prior to performing any corrective maintenance. Disassembly of the valve should be accomplished in accordance with the procedure supplied in the following sections. After repairing the valve, the operating mechanism should be cycled through one complete operating cycle. With full line pressure applied to the valve in the open position, an inspection should be made to detect leakage in the areas around the seal plate, bonnet, packing gland, and body-end connections. A record should be made to indicate that the valve has been repaired and is in working 

Lcondition. Any marking that the valve is inoperable should be removed. In addition, fire department and other appropriate municipal departments should be informed
of satisfactory repair of the valve.
UPPER O-RING RETAINER,
O-RING REPLACEMENT
Note: Shut off the pressurized pipeline and depressurize it.
1. Turn the Disc Assembly (F807) to the closed position.
2. Support the Gearbox (F811) safely.
3. Remove the Gearbox Bolts (F814) using an open end wrench.
Set the Gearbox Bolts (F814), and Gearbox Washers (F815)
aside for use during re-assembly. (See Fig. 2A)
4. Remove the eight, Upper O-ring Retainer Screws (F836)
from the Upper O-ring Retainer (F839) using an allen wrench.
(See Fig. 2B)
5. Remove old, Upper O-ring Retainer Inner O-rings (F837) and
Upper O-ring Retainer Outer Orings. (F838)
6. Clean Seal House. (F839)
7. Grease and install new o-rings.
8. Re-install in reverse order and tighten screws.

END PLATE O-RING REPLACEMENT
Note: Shut off the pressurized pipeline and depressurize it.
1. Turn the Disc Assembly (F807) to the closed position.
2. Remove the four End Plate Bolts (F827), End Plate Washers
(F826), and End Plate (F825) using an allen wrench.
(See Fig. 2C)
3. Remove old End Plate Dust O-ring (F843) and Axial Thrust
Bearing Gasket (F856).
4. Clean End Plate. (F825)
5. Grease and install new o-ring. Replace Axial Thrust
Bearing Gasket (F856).
6. Re-install in reverse order and tighten screws

LOWER O-RING RETAINER,
O-RING REPLACEMENT
Note: Shut off the pressurized pipeline and depressurize it.
1. Follow intructions to remove End Plate.
2. Remove the four End Plate Bolts (F827), End Plate Washers
(F826), and End Plate (F825) using an allen wrench.
(See Fig. 2C)


3. Remove old End Plate Dust O-ring (F843) and Axial Thrust
Bearing Gasket (F856).
4. Clean End Plate. (F825)
5. Grease and install new o-ring. Replace Axial Thrust
Bearing Gasket (F856).
6. Remove the eight Lower O-ring Retainer Mounting Screws
(F860) (See Fig. 2D)
7. Remove the Lower O-ring Retainer (F862), along with the
Lower O-ring Retainer Inner O-rings (F861), and Lower O-ring
Retainer Outer O-rings (F863).
8. Remove the old o-rings from the Lower O-ring Retainer
(F862).
9. Clean the Lower O-ring Retainer (F862) and install new orings
(F861) and (F863).
10. Re-install in reverse order and tighten screws.