Service Competence Center   HYDROPNEU Assembly instructions · M3 - Assembly of piston seals The piston seal is a two-piece seal consisting of one O-ring made of the material NBR and one piston ring made of a Teflon compound. Both seal parts are built into the groove in such a way that the elastic O-ring underneath pre-tenses the piston annulus on top. Progress of the assembly: The O-ring is buttoned into the groove which is situated in the piston center with the help of a seal bailer. Be careful not to damage the O-ring by sharp edges at the tool or the piston and do not install it in a distorted way. Then the piston annulus is drawn over a cone (outside diameter of cone = outside diameter of piston) and thereby extended. Next the extension cone is put directly on top of the piston and the piston annulus is pushed onto the piston until it is placed in the groove. In order to get a re-deformation to the nominal size, the piston with the installed seal must be lead into a calibrating device (conical leading-in slant, smallest diameter = nominal diameter). Approx. after one minute the re-deformation is finished. For the sealing between the piston rod and the piston, an O-ring has to be buttoned-in into the groove in front of the internal thread. Again be careful not to damage the O-ring or to install it in a distorted way. Before screwing the piston into the piston rod, the O-ring inside has to be greased slightly. With the help of a frontal punch wrench, the piston is firmly tightened on the piston rod. Now the piston rod is drilled slightly through the tapped hole of the piston, so that the tip of the grub screw can block the rotating of the piston. After putting some lock-tight glue on the locking screw it is tightened firmly. As a last step the slackness between the damping disc and the damping piston has to be checked. The disc should be easy to push onto the piston with minimum slackness. Print the assembly instructions…  Back