Instruction Manual
D104483X012
785C Actuator
May 2022
30
Disassembling the Handpump Hydraulic Cylinder
WARNING
Refer to the WARNING at the beginning of the Maintenance section in this instruction manual.
If there are leaks in the 785C Actuator manual handpump hydraulic cylinder, a malfunction in the mechanical
components, or in case of scheduled preventive maintenance, the actuator must be disassembled, and the seals must
be replaced with reference to the sectional drawings and following procedures:
1. Deenergize the actuator and valve assembly.
2. Drain the hydraulic fluid from the piston via the drain ports.
3. Remove the nuts (key 2714) from the tie rods (key 2713) at the end flange (key 2712) side.
4. Slide off the end flange and the hydraulic cylinder (key 2711).
5. Slide off the piston rod (key 2706) from the head flange (key 2701).
Handpump Hydraulic Cylinder Seals Replacement
1. Prior to reassembly check that the actuator components are in good condition.
2. Lubricate all mating surfaces with recommended lubricant (see table 11).
3. If the O-ring must be replaced, remove the existing one from its groove, clean the groove carefully and lubricate it
with protective oil film. Assemble the new O-ring into its groove and lubricate.
4. Replace the O-rings (key 2708) of the head flange (key 2701).
5. Replace the O-ring (key 2708) of the end flange (key 2712)
.
For replacement of piston rod seal ring (key 2705) and of the O-ring (key 2704) proceed as follows:
1. Remove the existing PTFE seal ring (key 2705) and the O-ring (key 2704) from their groove.
2. Clean the groove carefully and lubricate.
3. Assemble the new O-ring (key 2704) into its groove and lubricate.
4. Assemble the new PTFE seal ring (key 2705) into the flange groove, on the rubber O-ring (key 2704), by bending it.
Take care bend the seal the least amount required
.
5. Enlarge the seal ring with your fingers to restore its round shape. Pay attention not to utilize any tools, which can
damage the seal ring.
For replacement of piston rod seal ring (key 2710) and of the O-ring (key 2709) proceed as follows:
1. Remove the existing PTFE seal ring (key 2710) and the O-ring (key 2709) from their groove.
2. Clean the groove carefully and lubricate.
3. Assemble the new O-ring (key 2709) into its groove and lubricate.
4. Assemble the new PTFE seal ring (key 2710) on its rubber O-ring by introducing one side into the groove and then
enlarge it with your fingers so as to seat it into the groove. Take care to enlarge it uniformly without any tools which
could possibly damage it. The elastic memory of the of the PTFE the seal ring will allow the ring to shrink back to its
previous dimension.
Handpump Hydraulic Cylinder Reassembling
1. Assemble the new gasket (key 2624) after cleaning the surfaces of pneumatic cylinder head flange (key 2210),
spacer (key 2622) and head flange hydraulic (key 2701) which are in contact.