Steerer Tube Nut detached from Stem Bolt

[mnichols]

Not sure if I've I'm using the correct terminology so let me describe what has happened

I'm rebuilding my old Enigma Etape frame which has been hung up in the garage for a while. The fork was still attached to the bike, and although there was no stem, the spacers, cap and bolt were still in place.

When I put the stem on and tightened the bolt at the top I notice I wasn't getting any purchased. I lifted the bolt out to inspect and the bit that should be attached to the top of the Steerer Tube came out with it. I can hear the bit that this should be screwed to ratting around in the fork and if I turn it upside down I can get it to come to the top where I could theoretically screw it back on, but as there is no tension I cannot screw it back together. The nut in the fork isn't star shaped it's just a nut rattling around

Can I fix this?

[mnichols]

Ok, I did a bit searching on youtube and I guessed that it's a compression fitting that has come apart

The bit that I thought was a lip on the fork is part of the fitting, and I managed to lift that out, shake the nut out, remake the unit and reattach it all

So, it seems ok, but is this normal, should I replace the compression fitting? If so, any recommendations?

[slowster]

It sounds like you are not tightening the bolt that expands the steerer bung sufficiently to get it to stay in place when you subsequently tighten the bolt in the top cap to pre-load the headset bearings.

Typically you need to use a 6mm allen key to tighten the bung. Usually there is a maximum recommended torque measurement on the bung lip (typically 8Nm), although to reduce the risk of damaging a carbon steerer I prefer to tighten it quite a bit less than that, i.e. just enough to get it to stay in place when later tightening the bolt in the top cap is all that it needs. Using carbon grip paste on the bung will potentially allow you to reduce the torque needed as well.

[Marcus Aurelius]

It’s a compression plug. Torque it up to 7 Nm then it should stay in place. It’s an anchor point to tension your headset with.

[mnichols]

OK, so don't need to get a new one just make sure it's tight enough