I managed to put a few ml of 10wt oil in my seatpost, which has stopped the up and down play, but when I took the post apart, I think an o-ring came out of the outer sleave. I dont remember seeing this before when I’ve cleaned the post, and the post seems to operate fine without it. It’s about 1″ diameter.

Any idea where this goes? Is it used as a bottom out bumper (as that feels a bit harsh at the moment).

The post is holding air and oil, so pretty sure it isnt used as a seal.

thanks

When I stripped mine down an o ring felt out and had a chunk out of it as though it had got dry and rolled up on the mechanism – wasn’t an inch across though – more like 20mm tops. I think you’re right that it’s a bottom out bumper and I think it goes behind the ‘piston’ bit.

By the way I found a good way of getting the oil in was to push a GT85 red tube into a syringe nozzle as you can then gently squirt the oil in without having air bubbles pushing it out.

where are you squirting the oil in? can you just remove the schrader core and pump a bit in?