Removing stanchions from USD fork alloy lower legs.

[Riejufixing]

Write-up for this operation done on a Rieju RS3 125cc. Likely applicable to other machines.

Removing the screw-in stanchions was quite an easy job, but probably best done with a helper, as I had! He took a couple of photos, so I will try to upload them.

Materials for the undoing operation:

Your forks, completely dismantled down to the stanchion and lower leg, not forgetting to remove any bolt inserted from underneath the lower leg (above the wheel spindle). Rieju RS3 forks use 12mm hexagon-socket bolts inserted from underneath. Wipe off any oil as far as possible inside and out.

A vice with soft jaws, e.g. pieces of alloy angle overlaid.

A gas torch with a decent sized flame. A "weed wand" might do. I used a propane torch with a 1" burner.

A tommy bar about 1'/300mm long (or longish screwdriver).


1) Clamp the lower leg upright in a vice, positioning the soft jaws over the spindle hole, taking care they don't foul the calipher mount, etc.

2) Heat up the lower leg nice and quickly, playing the torch over the whole length from the top to where the threads in the bottom are. Don't directly heat the stanchion!

3) When the lower leg is hot enough (applied spit will not stick/bounces off), turn the stanchion using your tommy bar passed through the holes at the top of the stanchion. Keep the lower fork leg hot while you do this.

4) When it's unscrewed, rotate and pull the stanchion 'till it's out.


There is a Youtube video of the same procedure: https://www.youtube.com/watch?v=wADxhvP40Rw however, their gas torch does not put out much heat, so theirs was a slow process more difficult than it needed to be. This video mentoins "thread seal". No sealant was used on the Rieju forks this write-up referrs to. I am not at all sure that any sealant was in use on their forks either. There was some alloy corrosion between the stanchion and lower leg that filled a few of the threads on the stanchion, giving the appearance, perhaps, of scorched thread sealant. The corrosion was, I think, what made unscrewing "impossible" without heat.

See: https://www.bikechatforums.com/viewtopic.php?t=325160

For what it's worth:

[sickpup]

There should be thread sealant used as both an oil seal and a form of adhesive. Otherwise good write up and applicable to a lot of USD Stanchions where they enter the knuckle.
Some forks such as early Ducati Monster use a grub screw to locate the stanchion in the knuckle but most are a screw thread.

[Riejufixing]