I have a vintage frame of Reynolds 531 tubing. I added a longer stem two years ago. Now I need to remove that to send the frame in for repair. The problem is that I can't get the expander to descend. I have loosened the bolt and hammered it, but it has not budged.

It is a smallish frame, the seat tube is 52cm c-c
Could this be bottomed out against the narrow butted part of the steerer tube? Are steerer tubes butted?

I have read dozens of posts and pages related to stuck stems, and I realize this may be bonded, but the steel expander should release in any case.

How to proceed?

grab a real good flashlight and take a look. It is possible the wedge is wedged against the butting. If that is the case and you can find a willing helper I would try turning the bike over, holding a block of wood in the crook of the stem and bang on that once or twice while the helper holds the bike steady.

Thanks for the quick reply!
I can see it clearly. It is far enough down I can touch it with my index finger. I don't see any room or stem around it. The stem forms an obtuse angle, so I will have to figure out a way to hammer up on it.
I am concerned that pounding up from the bottom would drive the wedge into the stem, unless they both move up together.

Place the block under the extension of the stem- in front of the head tube, not inside it. Then give it a few whacks with a hammer.

If you didn't over-tighten the stem when you installed it, and the bar is still on, you can try twisting it a bit. Be careful not to get carried away if you're holding the fork by the front wheels between your legs, because you can twist the fork blades. If you want to try twisting harder, hold the folk crown in a vise between two wood blocks. Now tou can twist the bar while pulling up. Once you've moved it a millimeter or two, you can drive the wedge down and free the stem.

Back in the bronze age, we made it a point to only tighten stems race tight. That's tight enough to hold for steering, but loose enough to twist in a crash. That protected front wheels and forks from added damage if the wheel swung around until the bar hit. If yours is only race tight, you'll be able to wist it, and work it up enough to free the wedge without too much effort.

Also would be a good idea to spray some PB-Blaster onto the wedge. Remove the bolt completely and put the spray-straw up though the wedge's hole from the bottom and spray liberally. Also spray some down from the top in the gap between the steerer-tube and stem's quill. Let sit overnight.

I've had some severely corroded and stuck seatposts that I couldn't force free with gorilla force on the seat. Even bent the seat-rails in the attempt. Sprayed some PB-Blaster on it and let sit overnight. In the morning, the previously frozen seatpost had sunken all the way down into the seattube from just the weight of the seat.

Thanks Danno. Brute force did nothing, so PB-B is next.

I'm just a noob here, but fwiw, it might very well be that aluminum oxide has formed between the stem and the tube, effectively gluing it into place; if you had a way of immersing the fork, stem, and HT in a tub of household ammonia for, say- maybe 48 hours? It might dissolve enough of the Al2O3 for penetrating oil to do it's thing.

I had a similar problem a few years back with an RB-2 whose PO had managed to ovalize the steerer with a stuck wedge. After soaking the fork in ammonia for two days and slopping it for two more with Liquid Wrench, I screwed an old stem bolt into the wedge from the bottom (from the inside of the fork crown), braced the top of the steerer against a 2 x 4, and gave it four solid whacks with a mallet; popped the wedge right out.

Success!
PBB freed up the wedge to move down. The aluminum stem was still fused to the steel steerer. Soaking with PBB, alternating heat and cold, and soaking in ammonia did not help. I used a hacksaw blade to saw inside the stem so it was partially split with 4 separate cuts. I then compressed it with pliers, and reapplied the PBB. I was then able to twist it out.

Thanks to all for your help!