_____________________________________________________________________________________
STI S.r.l.
– Via Dei Caravaggi 15, 24040 Levate (BG) – ITALY www.imi-critical.com
Manual 5400, rev. 05 02/2018
– RTQHS
24
8.2.2 hydraulic cylinder seals replacement
Warning
To release spring tension, the stop screw at the end of spring cartridge must be
remove before the cylinder tie rods are opened
.
Fig. 16
– Hydraulic cylinder seals replacement
In case of necessity, in order to replace the seals, it is possible to completely disassemble the cylinder in the
field without disconnecting it from the actuator body.
Warning
Ensure that the spring is totally released and therefore the piston rod is totally
retracted.
Remove the nuts (2.8) ) from tie rods, remove the end flange (2.20) after that replace the o-ring (2.16) and
back-up ring (2.2) from the seal groove.
Disassemble the cylinder tube (2.4) to replace the sliding guides (2.9) and piston seal (2.10) from the seal
groove and the o-ring (2.16) and back-up ring (2.2) on the head flange (2.19).
Remove the nut (2.5) from the piston rod (2.17), remove the piston (2.11) and replace the O-ring (2.15) and
back-up rings.
Unscrew the screws (2.22), disassemble the flange (2.7) and replace the piston rod Seal-ring (2.12).
Remove the nut (4.3) holding the travel stop (4.2) and the washer (4.1) and then, if necessary, replace the
sealing washer (4.4).
Before re-assemble clean all seal grooves carefully and lubricate them with protective oil or grease film.
It is possible to disassemble and replace seals of hydraulic cylinder disconnecting it from the actuator body
and bring it in a safe area.
