I think the bike sat outside for a long time by the previous owner. There is rust around where the fork meets the frame. It squeeks on turns, so the ball bearings need grease. I would like to rebuild that area, which means removing the stem and the fork.
The bolt that causes the stem to clamp down is easily loosened. When it’s out by 5mm or so, I can easily tap it down with a hammer. So the wedge at the bottom can move freely. But no matter how loose that is, the stem is one with the fork. I have sprayed a good amount of wd-40 and it has had plenty of time to soak.
I have tried removing the wheel, then having the fork straddle someting strong, and tried forcing the handlebars to twist. That just caused the fork to spread. I actually had to correct that by clamping the fork back in place so it could slip onto the axle again.
With the wheel off, I tried banging on a steel rod from the bottom side. I did not want to damage the wedge so I limited the amount of shock I was willing to deliver.
What do pros do in this situation?
PB Blaster is the goat penetrating oil. Spray a bunch on and let it sit for a few hours. Spray some more, then a little percussive persuasion. If that doesn’t free things up, careful use of intense heat is next.
This. You want penetrating oil not wd40. Right tool for the job.
Next step is a better lubricant I think, you want to try whatever penetrating oil you can get your hands on and really soak as much in as you can, from the top and the underside of the fork.
Leave that overnight to work and then try loosening it again. Might be an idea to put an old handlebar or rod in the stem for leverage, and obviously clamp the fork as best you can.
After that it’s heat usually I think. Im not a pro but these would be my next moves
WD40 isn’t a penetrant, so really won’t help.
PB Blaster is the best I’ve found. If you can’t find it, there’s some recipes online (backed by testing) for making your own from ATF and a couple other things. I’ll see if I can find one.
That it won’t twist out means it’s really in there.
If you completely remove the bolt, the wedge should drop out. That will leave room to try to tap it out from the bottom after it’s had some penetrant soaking for a day or two.
Someone recommended heat too, which is a good idea as the aluminum and steel expand at different rates.
Long term (after it’s removed) - I’ve always used a never seize product especially with dissimilar metals. With this you’d want the thinnest coating possible because it relies on friction.
If the wedge is loose and the stem still won’t budge, the stem needs to be drilled out. Take it to a shop.
https://www.sheldonbrown.com/brandt/stuck-stem.htmlAssuming the stem is aluminum, and the steerer is steel?
Heat up with a torch. Soak it from the bottom using ammonia. Repeat for 2-3 days.
You can also just cut it out or drill it out.
Wouldn’t banging the wedge from the bottom tighten it?
(Joke solution) Leave the bolt loose, ride it down a steep gravel hill. It’ll definitely detach at the least opportune moment.
Is the wedge rubber? Could try putting something on it to soften it, or using a heat gun from the bottom?
(Not a pro)