Flowserve Tandem Rotary Actuators - Manual (Page 3)

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removing both sets of yoke plate bolts.
8. Remove the spiral snap-ring holding the sliding seal
assembly in place.
9. Remove the top clamp, sliding seal collar and base
seal. The base seal can usually be removed by hand
or by gently prying the inside lip of the seal upward.
WARNING: Do not scratch the top surface of the
base seal with a screw driver or sharp object.
Scratches can cause excessive wear and pos-
sible leakage.
10. Remove the transfer case cover plate.
11. Referring to the appropriate Maintenance Instruc-
tions, remove the positioner from the transfer case.
12. Remove the snap-ring from the shaft to allow the
lever arm to slide off. Slide the lever arm off the shaft.
NOTE: If the rod end bearing needs replacement,
remove the cotter pin and the pivot pin that holds the
rod end to the lever arm out of the lever arm. On the
200, and dual 200, a solid clevis pin with cotter pin
retainer is used.
13. Using a socket wrench and proper-length extension,
insert the wrench through the transfer case and
remove the four case bolts holding the transfer case
to the valve body.
14. Remove the transfer case from the valve body, being
careful not to damage the shaft.
NOTE: If the shaft bearing is to be replaced, push it
out with a press.
Reassembling the Actuator
To reassemble the actuator, refer again to Figure 1:
1. Clean and lubricate all internal parts. All O-rings
should be replaced and lubricated using a silicone
lubricant (Dow Corning 55M or equivalent). The bore
that houses the sliding seal assembly in the transfer
case must be smooth and clean.
2. Reassemble the sliding seal assembly by pushing
the base seal into the transfer case. Place the sliding
seal collar on top of the base seal so that the raised
portion of the sliding collar protrudes through the hole
in the top clamp.
3. Replace the top clamp and the spiral snap-ring.
CAUTION: Avoid pinching or twisting the dia-
phragm seal while clamping it down.
4. If the rod end bearings have been removed, press a
new bearing into each rod end. Reinstall each rod
end into the lever arm by inserting the pivot pin
through the lever arm and rod end bearing. Replace
the cotter pin in the hole of the pivot pin.
5. If the shaft bearing has been removed, press a new
bearing into the transfer case. When pressing shaft
bearings into the transfer case, the bearings may
have to be ground out to fit the shaft bearing.
6. Use a socket wrench and proper-length extension to
reinstall the four body bolts, attaching the transfer
case to the valve body.
6. If possible, check for correct fail-safe action. Position
the valve to mid-stroke and shut off the air supply or
disconnect the instrument signal. By observing the
indicator plate, the disc should either fail open, closed,
or in place, depending on the air failure action. If the
failure action does not operate correctly, refer to the
“Troubleshooting” section.
7. Spray soap solution around the cylinder retaining
ring, the adjusting screw, and actuator stem seal (this
should be done when the cover plate is removed) to
check for air leaks through the O-rings and adjusting
screw gaskets.
8. Check all air connections for leaks. Tighten or replace
any leaky lines.
9. Check positioner calibration by observing the gauges
and the disc position indicator plate. Make sure
positioner is calibrated to correct range. For the Sys-
tem 80 Positioner, push positioner cleanout plunger
several times to clear any possible restrictions.
10. When using an air filter, check and replace the
cartridge if necessary.
DISASSEMBLY AND REASSEMBLY
Removing Valve From Line
See Maintenance Instructions 10, Valdisk Control Valves,
for instructions for removing the tandem rotary valve from
the service line.
Disassembling the Actuator
Because of the tandem actuator design, it is necessary to
disassemble the actuator before removing the valve body
from the transfer case. Refer to Figure 1:
1. Disconnect all tubing from the actuator.
2. Relieve the spring compression from both cylinders
by removing both adjusting screws.
WARNING: Failure to do so may result in per-
sonal injury.
3. Using a screwdriver, remove the cylinder retaining
ring from the groove at the base of each cylinder.
4. Pull both cylinders off the transfer case and pistons.
NOTE: Substantial O-ring resistance may be felt.
WARNING: Do not use air pressure to remove
cylinder. Personal injury and damage to valve
parts may result.
5. Remove both spring buttons and springs.
6. Using each piston as a handwheel, turn each until the
actuator stem screws out of its rod end. Pull the
piston/actuator stem assembly out of transfer case.
CAUTION: Care must be taken not to damage the
sliding seal assembly or actuator stem O-ring
when removing the actuator stem.
7. If the piston, piston stem O-ring, or actuator stem is to
be replaced, remove the actuator stem locknut from
actuator stem and slide spring guide, piston O-ring
and piston off the actuator stem. If desired, the yoke
plates can be removed from the transfer case by