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My crappy bike (Aldo Cadenazzi) was squeaking for the last two days. Then today the stem broke. Luckily I was very slow when it happened.

How can I fix it? I have read a little bit about threadless and threaded stems, but I am not sure if a threadless stem will fit to this old bike. (I am not even sure if it is worth it)

enter image description here

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    Is your photo supposed to show the broken stem, or the stem before it broke? I don't see any "broken-ness" where the arrow points... – anderas Nov 5 '18 at 7:26
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    @anderas If I zoom into the image, it looks like the weldseam has a gap to the stem. – Uwe Keim Nov 5 '18 at 11:45
  • @anderas it is broken from the connection point. I didn't fully break it and take it off to avoid giving the bike an abandoned look. So authorities do not collect it as scrap. – nimcap Nov 5 '18 at 12:29
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Just replace it. The part is called quill stem, it is not threadless-compatible, and it is still widely used. The only type of quill stems I heard of have 1 inch diameter, so you can just find one that is of the same/similar height and length.

The simplest is to take it to a local bike shop and they will do it for you. If you want to replace it yourself, get a wrench that can undo those two bolts at the top of your picture (hard to tell, but I think it is something in 12 - 15 mm range).

Unscrew the stem from the frame and from the handlebars; grease the new stem's shaft that goes into the fork with any sort of machine oil/grease you have; then screw it back into the fork and attach the handlebars.

It may happen that the fork-stem surfaces have rusted together if no grease was used at installation time. In this case, you will have a hard time removing the stem. Look for advice on this site how to help it.

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    Two comments to an otherwise good answer: 1) There are at least two diameters of quill stems in use. 2) You may want to add, that removal of the vertical screw may require first screwing it out by a few millimeters, and then to hit it with a hammer from above. This is the most effective way to loosen a rusted quill stem. The hammer stroke will push down the bottom part that exists to lock the stem in place. After that it's usually just a matter of applying enough torque on the stem to loosen the upper part as well. – cmaster Nov 5 '18 at 8:16
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    A short comment to @cmaster - hitting the vertical screw is supposed to loosen the expander or the wedge (depending on which system is used) and not the quill stem itself. It should be possible to remove the (broken) stem by twisting it and working it up. Most likely a pipe wrench will come handy here as this stem does not have any lever to twist it at the moment. – Mike Nov 5 '18 at 9:16
  • @Mike The handlebar is a perfect lever for twisting, as is the front wheel. I usually put the front wheel between my knees and use my arms to twist the handlebar. Works perfectly most of the time. – cmaster Nov 5 '18 at 9:59
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    @cmaster, I totally agree, provided that the quill stem is intact. Looking at the photo the OP sent I believe that the handlebar is not attached to the stem anymore and only the top bolt keeps it from rotating excessively. – Mike Nov 5 '18 at 10:55
  • Agreed - some parts are just not worth trying to fix, like brakes, handlebars, and stems. Once compromised, their function becomes questionable. Remember, teeth don't grow back. – Criggie♦ Nov 5 '18 at 12:05

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