I agree with Dale on the size issue - the stem is not the "wrong size" - it's just corroded in place. I agree on the Kroil, but in my experience this quite often won't be enough, no matter how long you soak it. Heat _may_ help break it loose, but I'm not a big fan of it here, and don't do the twisting while it's hot. The thermal expansion coefficient of aluminum is much higher than that of steel, so when you heat the assembly, the Al expands more than the steel, making the fit even tighter. Extreme _cooling_ is more likely to help you break it free, because the stem will shrink more than the steerer.
But the key is to dissolve the corrosion "stuff" that's between the
steerer and stem (mostly aluminum oxide), which is what's locking the
stem in place. Ammonia is the right stuff for that. See
http://www.sheldonbrown.com/
Mark Bulgier Seattle WA USA
Dale wrote:
> << Wouldn't you know it, some jerk apparently hammered the wrong size
> stem into the steerer tube?>>
>
> No, that steerer is the largest "hole" made in that era.
>
> Have you used "Kroil"? absolutely great stuff.. but it would
logically
> take 3-4 days of applications, soaking, tapping with hard rubber
> hammer, etc.
>
> << The shop owner says a torch, but this qualifies as a special case
> because the stem is aluminum and so is the pitifull frame. >>
>
> The fork steerer, what the stem is really stuck in, is steel...
> hacksaw the frame away from the fork and steerer. Then use heat on the
> steerer. Not enough to melt the stem (doh!) but to loosen all the
gunk.
> Clamp the fork crown in a big vise, then put some bars in the stem and
> start twisting and pulling...