Ive owned an XLC (advent in the USA i think) dropper post for about a year and it broke last week end.
Before reading watch this video, follows all the steps needed except the string replacement:
HOW TO SERVICE – Brand X Ascend 2 Dropper Seatpost – YouTube
This particular model has a out side the seat clamp mechanism rather that lower. A string inside the housing pulls the lever that operates the mechanism. The original is quite thin when compared with the thinnest sting i could on OBI (OBI is trash btw). the string was 1.6mm or 1.8mm cant remember. BUY EXTRA YOU WILL PROBABLY MESS UP. took me a few tries.
Look at the second picture
The eyeholes where the operating string weaves through are quite small so you are most likely going to have to modify your new nylon string. i used a lighter and pliers to give it a very gradual cone shape. open your windows dont breath the plastic. route it down the dropper housing and reuse the cone shaped end for the bolt with the eyehole.
cut extra material finish assembly.
Make sure everything is align the string is thicker so you have lower tolerance. look at it carefully. you'll be fine.
Hardest part is getting the thicker string through the eyeholes.
by TheRatKing450