Stuck stem/headset

[Tim Hall]

The Mercian has a Stronglight A9 threaded headset and a quill stem. Currently the front light is bolted to an old style brake hanger, which in turn is gripped between the headset upper nut and lock nut. There is play, allowing the light to swivel sideways. Easy, I thought, grab head set spanners and give it some welly. Except the lock nut is siezed solid on the steerer. I suspect it's aluminium meets steel interaction. So I loosened the quill bolt (which was easy) and tapped it to release the wedge, which moved with little fuss.

But the stem won't shift in the steerer. More Al vs FE corrosion I suspect.

Clouting it with a medium sized hammer had no effect. Removing the front wheel, resting the forks on a piece of wood (to remove the bounce due to the tyre) and clouting with a medium sized hammer had no effect.

Trying a GBFO spanner on the lock nut didn't shift it.

Next up is removing mudguard, resting the inside of the fork crown on a lump of wood and applying a bigger hammer.

Having noticed a Crack of Doom in the rising part of the stem, where it exits the headest, surgery can be applied. I'm thinking of cutting the lock nut off, but how to remove the stem?

WWSD?

 

[KneesUp]

I had a stuck stem recently. I tried:

1) Hitting it with a hammer
2) Hitting it with a larger hammer
3) Twisting it
4) Twisting it harder
5) Blocking up all the holes, turning it upside down and filling it with vinegar (it softens the rust, apparently) and then hitting it
6) Blocking up all the holes, turning it upside down and filling it with penetrating oil and then hitting it
7) Sawing the stem off above the nut to get the forks off.

At this point I was going to dissolve the aluminium stem with casustic soda but before I did it occurred to me to check if it was aluminium with a magnet. It wasn't, it was steel. Well done me

So I left it in the corner of the kitchen for a few weeks and scowled at it, but that didn't work either. So I took it to my local garage who put the forks in a vice, heated them up with a blow-torch and smacked the remaining stem out with a metal bar and a lump hammer

 

[Apollonius]

I think heat might be the answer. Not only do you get differential expansion, but the heat breaks the chemical bond caused by corrosion.

 

[KneesUp]

If you've previously filled the stem with vinegar and penetrating oil, you also get some funky coloured flames from the blow torch (or maybe that was the remaining paint being scorched off?)

 

[accountantpete]

Hope you have freed the stem.

If not - then the use of a hammer is my weapon of choice in this situation.

The thing is - you have to get really medieval with it.

Tool up to go to war and give it the most fiercesome blow imaginable (so not recommended if the frame is very valuable).