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pablo pinchasso
11-21-2011, 10:32 PM
My neighbor has his daughters bike a Trek ( aluminum frame early 90's vintage ) and the Cinelli 1-A stem is frozen in place... I am trying to help him remove it so he can put a shorter stem on it.

I have no idea if the steering tube is alumnum or steel. other than drilling it out has any one come up with a good chemical to cut the aluminum corrosion that causes this...??

ultraman6970
11-21-2011, 10:49 PM
has to be steel...

stupid questions... did u hammer the wedge cone bolt??

trangalang
11-21-2011, 10:52 PM
Frozen as in the insertion of the stem is stuck in the headtube, or frozen as in the wedge is stuck in the headtube making it too tight to remove? If the wedge is stuck, loosen the stem bolt (not all the way, leave some threads in there) and tap it out with a hammer.

If there's too much corrosion causing the insertion portion of the stem to be stuck in the head tube, you can try spraying it with WD40 or pouring hot water in the headtube from the fork/bottom. The aluminium/steel should expand slightly just enough to get it loose.

zmudshark
11-21-2011, 11:14 PM
I'm going to assume that you loosened the top bolt a bit, still leaving it threaded into the expanding cone, and then struck it with a dead blow hammer, or a hammer with a block of wood between it and the bolt to free it?

If you did this, and the bolt is loose, but the stem wont move, report back. You may have some work ahead of you.

This is a start, but there are other thing you can try before you hacksaw it out: http://www.parktool.com/blog/repair-help/seized-seatposts-and-stems

oliver1850
11-21-2011, 11:57 PM
Your steerer is surely steel, which is why it's stuck. Dissimilar metals and galvanic corrosion.

I've heard that Coca-Cola works, but haven't tried it.

bart998
11-22-2011, 12:38 AM
Ammonia dissolves aluminum oxidation. If it is really stuck I've had good luck with CRC Freeze-off (any auto parts store). Penetrating oil and C02, spray on the stem for 30 seconds to a minute, twist stem in steerer... the cold helps loosen the stem so the oil can penetrate. Of course the wedge should be out before you do this.

EricEstlund
11-22-2011, 02:29 AM
Need be, flip the bike, pour in the penetrating oil from the bottom of the fork and let it soak overnight.

farmallguy
11-22-2011, 07:29 AM
I have used vinegar to remove steel bolts frozen in alloy heads. let it soak for a day or so keeping it wet with the vinegar.

jack

corsaspeciale
11-22-2011, 07:43 AM
My neighbor has his daughters bike a Trek ( aluminum frame early 90's vintage ) and the Cinelli 1-A stem is frozen in place... I am trying to help him remove it so he can put a shorter stem on it.

I have no idea if the steering tube is alumnum or steel. other than drilling it out has any one come up with a good chemical to cut the aluminum corrosion that causes this...??
Try Kroil it is one of the best penetrating oils out there.
http://www.kanolabs.com/

pablo pinchasso
11-22-2011, 08:06 AM
used Kroil and the stem wedge is loose. I am thinking about getting some aluminum wheel cleaner. I had a uck " buik" back in the 80's that had cast aluminum wheels and I used spray acid to clean the machined finish...will see it is real tight. no grease when the shop built is.....

ultraman6970
11-22-2011, 08:47 AM
Well probably they built it with grease but if the bike has been years stored and the stem has not been moved the grease pretty much dry then then humidity comes in and u have disaster, the other problem is that if the stem shaft is too long it could be stuck at the bottom of the fork, the bottom is conical in good bikes, and since u mentioned a girls bike then i dont think the bike is too big either. Stems must be moved at least once a year just to play safe, just lose the bolt and tiny twist to the stem then put it back in position.

Causes for this problem, no grease or almost no grease, centuries the stuff has been stored and not moved and the last one is small bikes, small bikes have tendency to get the stem stuck in the bottom of the fork.

Good luck with the PITA problem :D

used Kroil and the stem wedge is loose. I am thinking about getting some aluminum wheel cleaner. I had a uck " buik" back in the 80's that had cast aluminum wheels and I used spray acid to clean the machined finish...will see it is real tight. no grease when the shop built is.....

Birddog
11-22-2011, 08:52 AM
If you are using a penetrating fluid, you can speed the process by applying a pad sander (sans sandpaper) to the stem or possibly the fork. You could also use one of those multitools like the ones on the infomercials with a block of wood or something between the vibrating tool and the stem or fork. It really works and speeds up the penetrating process a lot. It also works on stuck seatpost.

Ti Designs
11-22-2011, 09:14 AM
If you are using a penetrating fluid, you can speed the process by applying a pad sander (sans sandpaper) to the stem or possibly the fork. You could also use one of those multitools like the ones on the infomercials with a block of wood or something between the vibrating tool and the stem or fork. It really works and speeds up the penetrating process a lot. It also works on stuck seatpost.

Or just skip to the air hammer... Honestly, the penetrating oil works, but we're talking tight tolerances and two surfaces that are just about welded together. At some point the application of force is needed. The trick then is not damaging the fork at or below the crown. Clamping a fork in a vice is tricky, I use 3/4" thick rubber jaws on my Wilson machine vice so I can clamp right at the crown. Most people use wood blocks to do the same thing. You're not trying to yank the stem out, just fill the gaps with solvent and get a slight bit of movement.