STI RTQ Series, Instruction Manual, Page: 29 / 44

STI S.r.l. – Via Dei Caravaggi 15, 24040 Levate (BG) – ITALY www.imi-critical.com
Manual 5300, rev. 09 06/2020 – RTQS 25
9.3.5 Scotch yoke Mechanism seals replacement
Fig. 16 –Scotch yoke mechanism seals replacement
To replace the cover gasket (1.8) under the cover (1.5), you should remove the position indicator (6.1, 6.2,
6.3) and all the screws (1.13, 1.14), before replace cover gasket clean the housing and cover.
After removing the cover you may disassemble the bushing (1.3) and replace the O-ring (1.15, 1.16).
Clean the seal groove carefully and lubricate it with protective oil or grease film.
Fig. 17 – Scotch yoke mechanism seals replacement.
Once perform these actions is possible to remove the gasket between actuator housing and cylinder (2):
Remove the screw (1.11) to disengage the guide block from spring cartridge, move the scotch yoke in
central position (45°) remove the screw (1.12) to disengage the 2 off half rings (1.17) from flange (1.9),
remove the fixing nut (5.3) on the cylinder side, remove, remove the cylinder (2) and replace the gasket
(5.2), before replace cylinder clean the surface of housing and cylinder head flange.