|Base of seat|
|Undo hex bolt to loosen the clamp that holds the seat pillar|
|Extract seat pillar from seat base|
Shows the 26mm OD rubber washer ready to insert into tube on seat base
|Push rubber washer down to bottom of seat base tube|
Insert tube and tighten VERY tight (I used a pair of pliers to hold the allen key to get the bolt nice and tight)
Note: The 25.5 & 25mm washers are a lot thinner than the 26mm ones. If anyone is using either of them instead of the thick 26mm ones, they'll need to use several of them .... for best results just under 1/4inch thickness is good.
Hope that helps