How to change a fork seal on an 1150

Welsh · Apr 30, 2012

So as I mentioned, I popped a fork seal yesterday on the Jericho to Assen sand road on one of the washouts I guess :biggrin:

I always keep a spare fork seal, so no going to BMW today (none left now), but I thought I would document it to show how simple an exercise it is on the pigs… 8)

Tools needed, 3mm allen key, 22mm open end spanner, 14mm socket 6 point 12 point rounds the nuts, this is a 6 point do we understand :

Taking an edge or small screwdriver prise out the cover, it should come easily

This is the nut you need the 14mm 6 point for

Hold the stanchion hex with the 22mm spanner and undo the 14mm nut

Push the stanchion down it should go easily and out of the way of the top triple crown

Withdraw the complete stanchion

Prise out the dust seal/scraper should also come out easy

You will see the seal and its retaining clip,

The clip comes out easily with a small flat head screwdriver

Then using a flat screwdriver lever the seal change sides to ease it out if tight, note which way up, the spring is on top

I then measure the volume of oil in the leg, each leg takes 450ml my calcs say 470mm of height I had 420mm on the piece of curtain rail measure, so I added 50ml, I use ATF its goods enough for these forks as they do not damp in the stanchions its lubrication only

Push the new seal in by hand using the old seal to protect it

Take out old seal and fit clip also by hand

Oil the stanchion and fit scraper

Oil the seal lip and gently insert the stanchion

Loosen this screw to bleed air as you push stanchion into roughly the right height to fit into top yoke

Tighten screw and push thread into bearing

Refit nuts and cap (BMW say that nut should get Loctite your choice)

Done