Simple headset. Can't thread bol

[Lien Sdrawde]

Just trying to fix my daughters cheap mountain bike. The only components are as pictured.
The bolt seats in the threaded hole at the bottom of the headset but not when the nut is in the tube - the nut has some slots on it, one of which seems to line up with a groove on the inner walls of the headset, but once I try to get the bolt seated when the nut is in the headset, it just won't work / take the thread.
Any ideas welcome.

 

[the snail]

Where's the stem? There should be a cone or wedge at the bottom of the stem that the bolt screws into.

 

[Lien Sdrawde]

Where's the stem? There should be a cone or wedge at the bottom of the stem that the bolt screws into.

Nowt in there. There was just what you see.

 

[the snail]

It looks like a threaded headset? What were the handlebars attached to?

https://www.parktool.com/blog/repair-help/stem-removal-installation-quill-stems

 

[Lien Sdrawde]

Erm. Nothing that I can see.

 

[the snail]

Yes, you're missing the wedge from the bottom of the stem. The bolt screws into that (part D in the diagram on the Park Tools page). If you haven't got that, you'll need a new stem.

 

[Lien Sdrawde]

Many thanks the snail.

 

[si_c]

The expander wedge has become unscrewed - if you look at the picture linked here you will see what is missing. As you tighten the bolt the bottom bit tightens against the top part and holds it in place.

There are a couple of possibilities, it's fallen out - in which case have a look for it, it's still in there - if you turn the forks upside down it might fall out and you can refit them together, alternatively it may have seized in there entirely which is not outside the realm of possibility for a bike if water has got in.

 

[Lien Sdrawde]

Ah ha. A good thwack with a hammer has dislodged this....

 

[Lien Sdrawde]

Tra laaa
Thanks again.

 

[I like Skol]

How old are you @Lien Sdrawde