Sinking Office Chair Hydraulic Cylinder Fix

This model fixed my sinking office chair for good.  Simply remove the clip on the very bottom of the chair holding the piston in place.  The shaft/piston is easily removed from the chair legs/base.  Slide the printed part on the shaft.  Put the parts back together with the original clip and it is fixed.  

This model was designed in FreeCAD 1.1 and is parametric.  You can change the inner and outer diameter of the part along with the height.  PETG was used with 4 vertical shells perimeters with a 15% 3D Honeycomb infill.  Printing the design on its side did not require any support material.  I did clean the hole after the print.

The part provide has default 10mm inner diameter, 25mm outer diameter, and height of 96mm.