Andy_K 

I've got a rusty old bike with a stuck stem that I'm trying to remove without destroying. The stem is aluminum, so from what I've read ammonia is in order, and maybe something to make it cold. My question is, how do I apply the ammonia to get it to stick around long enough to do its business and not just pour through the fork?

Andy_K 

Anyone? Anyone?

noglider 

I've never heard of using ammonia for working on bikes!

You loosened the expander bolt, right? The procedure is to loosen the part you can turn (with an allen key or whatever is appropriate) and then tapping on the bolt with a hammer. The bolt should go back down to its original height. Pull the stem by twisting it left and right while holding the wheel and fork stationary.

Is that the procedure you used?

If so, spray lots and lots of WD-40 in at the bottom of the stem. Bang the stem with a rubber mallot. Try again. Spray more WD-40. Repeat.

Andy_K 

Apparently ammonia is supposed to dissolve aluminum oxide, against which penetrating oil is apparently useless (so said Sheldon Brown). However, in searching for the Sheldon Brown link, I discovered that Jobst Brandt says ammonia won't work if the stem is truly frozen.

Anyway, yes, I did get the expander bolt loose with fairly little trouble, but even after that the stem won't budge. I've given it twice daily applications of penetrating oil for about a week, but I have observed no change (thus experimentally verifying the above claimed uselessness).

bikeman715

this may take up to 3 weeks before the stem will break lose. when you use the ammonia try hitting the stem with a soft hammer to vibes the stem as the ammonia works in. as far as the ammonia goes you need to buy it from a hardware store ( it stronger straights from what you will find in the supermarket.) also if you have a vise put the fork into it when you try to turn and break lose the stem.

DannoXYZ 

There are different types of penetrating oil and effectiveness levels. I've alwasy found PB-Blaster to work better than anything else. I'll spray down a stuck seatpost or stem and set the bike aside. Typically I'll come back after a couple hours and found the stem or seatpost has slipped down into the frame on its own.

keiththesnake

I had the same problem just a month ago. PB Blaster did the trick for me. Oh, and "tapping" isn't what worked. Once I unsrewed the allen wrench at the top of the stem just a few turns, I really whacked the allen head with a rubber mallet. Heard that satisfying, "tink," indicating that the wedge had released. Good luck.

Andy_K 

So where should I pour the ammonia and how much? Around the edges of the stem? Turn the frame upside down and pour it down the bottom? How do I keep it from pouring straight through?