lukeC

I have a "Frozen stem", Aluminimum Stem corroded and stuck in a Steel frame on an old Threaded Headset.

I'm trying to pour Ammonia down the Forks to slowly eat away the Aluminium Oxide But So far I have failed to get a good seal at the Stem Bolt Hole and the Ammonia just leaks away.

So far i've tried:

• Blue-Tac: I think the cold and metal conspire against it to stop it sticking
• Cork: I tried to whittle down an old wine bottle Cork but Its difficult to get A tight fit into the Bolt Hole without any gaps. The bolt hole is only recessed about 5mm
• Candle Wax: I stuck a bit of wax down and then tried dripping hot melted wax around it to melt a plug but it still leaks.

Any other suggestions? - what do people use for this kind of thing?


Secondly- I'm using "Cloudy Ammonia" that I picked up in the Supermarket in the Laundry section. Is this going to be a high enough concentrate?
I think it said 20g / Litre? maybe..

tellyho

I've never actually read an instance where this has worked, but I'll be psyched if you get it to.

I might cut out a section of a gallon jug, remove the handlebars and rest as much of the headtube in ammonia inside the jug as I could.

lukeC

I just put new Tape (with Adhesive Backing) on my handle bars so I don't really want to take them off. - and I'd probably need a few litres of Ammonia then.

HillRider

Try modeling clay.

Moochers_Dad

Electrical tape.

Bushman

if you dont mind scrapping the old stem, take a plumbers torch and heat up the stem at is base (where it enters the headset locknut). heat it up hot, then as it cools pour the ammonia in . The heat will expand the metal slightly( microscopic level) and as i cool it will draw the ammoina into the joint. you may need to do this several times, but i have used this method for years to break the bond between aluminium and steel.

lukeC

hmm, I don't really have easy access to a Plumbers Torch.
- Sounds a little hardcore for me.

I was intending to leave the Ammonia in there a couple of days.

I managed to get the Stem to turn the other day (by clamping the fork crowns and Applying CONSIDERABLE force through the handlebars.) however it didn't really move "vertically" at all.

mike

I never had much luck with the ammonia soak.

Did you try banging the living hell out of the stem with a hammer to bust the frozen stem?

Heat and force is the only thing that has ever worked for me trying to get aluminum and steel un-stuck.

mike

Oh, one more thing you can try is using an old seat post to go through the under-side of the fork and then bang the living hell out of the stem from the bottom side.

lukeC

the split piece bit at the bottom is still in the Fork
- the hole at the crown of the fork is too narrow for it to fit through so attempting to drive it out from below will not work I imagine.

The stem does turn in the fork but it is VERY Tight.

mike

mmmm....

Is it the typical quill type stem with a bolt that goes through the stem that pulls the wedge up to the stem to tighten?

TimJ

Hot glue gun.

lukeC

yeah I think its a Wedge. (Having never actually seen it.)

mike

If it is a wedge type, you should be able to remove the stem and handlebars completely.

Then use a piece of heavy guage pipe to insert into the head tube and pound the wedge out.

The wedge is always steel from my experience. Is the problem that the steel wedge is frozen to the aluminum head tube?

dafydd

if the fork is steel and you have access to a vise, you can gently clamp the fork (with wood blocks) in the vise to immobilize it, then use the bars/pipe/large wrench to twist it out. liberal use of penetrating oil will help.

tellyho

Great excuse to buy a torch. Seriously, if you're going to be removing stuck parts, it's a good go-to.

well biked

I've used an oak dowel in whatever size is just smaller than the inside diameter of the steerer tube. Put it in from the bottom, and beat the hell out of it. Worked for me-

tellyho

Just reviewing briefly; it doesn't sound like you've tried using the bolt to bang the wedge out: Thread the bolt back in loosely, so there's excess sticking out at the top of the stem. Use a piece of wood and hammer to bang the hell out of the bolt, knocking the wedge down. This has always worked for me.

neil0502

Dude.

You're my wrench from this day forward.

I like your style

mike

Thanks. You might appreciate my extensive hammer collection too. Big, small, rubber headed, steel heeded - I got 'am all. Bike parts can't resist 'em.

IMO, this job may call for the five pounder...

Bushman

not hardcore at all, its not like a welding torch, its handheld and much cooler temps. you can direct the flame right into the fork tube to warm up (warming does NOT affect integrity) the wedge .

plumber torch in use:

neil0502

Bernz-O-Matic, baby!

lukeC

I was actually just after tips on what to use to seal the bolt hole. I've tried these other things mostly.

to Summarise.

- The wedge is loose - it moves up and down but does not fit out the bottom of the fork tube.

- The STEM is most definately stuck. When Clamping the Fork Crowns I did manage to turn the stem in the hole but there was no way it was going to come "out" - it just turned in place. It took about 30 mins of messing around to even get the damn thing to MOVE at all.

- Most of these ideas are already mentioned in other threads. Where some people talk about using Ammonia but, hey, I really just can't think of much to use as a "plug".

TimJ

Hot. Glue.

I've done it and it worked. If you don't have a hot glue gun they're pretty inexpensive and really handy to have around.

noahjz

I don't know if anybody still cares about this thread, but I pretty much was in the same fix as the OP, the wedge had come completely loose and the aluminum stem wouldn't budge. I got a glue gun and sealed the bolt hole and let it dry for an hour, then i poured a bunch of cleaning ammonia in. The ammonia would slowly leak out of the stem, but I kept putting more in every hour or so. 4 hours later I was able to get the stem to twist. I worked on twisting it out for about 10 minutes and while I was making good progress it had started to get very tight again. I got out my mallet and whaled on it for a minute and it came out. So, in short, the glue gun, the ammonia, and the mallet all were instrumental in getting the stem out, all suggestions provided in this thread. Thanks! I will never use an aluminum stem in a steel frame again.