Bicycle Mechanics - Can't tighten OR loosen my stem/bar bolt.
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11-12-10, 07:56 PM
177957177958I have an old Peugeot with a pinch-bolt handle bar clamp. I went to adjust the handle bars and loosened the bolt and got the bars "just so" and when I went to tighten the bolt it just spun. I tried to loosen it and it just spun. I might be wrong but this thing, fully seated in the clam should NOT be spinning should it? How do I make it stop spinning? Is there hope of loosening or tightening this bolt? Where in the world can I get a replacement for a 30 year old stem-clam bolt?
Given it's age, I suspect that there may be some rust on the threads. You were able to loosen it because there was enough friction to hold the wedge. But with the wedge free, it now prefers to spin with the bolt rather than stick to the stem.
Your goal should be to lower the thread friction, while increasing the wedge/stem friction. I'd start with the latter. Try gently prying the bolt up, while turning it. If that doesn't work, remove the front brake and push the wedge up from the bottom while turning the bolt.
Lastly try getting some penetrating oil into the thread, but avoid getting it on the outside of the wedge.
11-12-10, 09:49 PM
FB seems to be speaking of the quill bolt
Handle bar clamping bolt... there should be a key in the bolt head,
and notch behind the front of that bolt to keep it from spinning ,
but maybe you stripped that out
I'd add thin penetrating oil and let it soak into the threads.
if the bolt still just rotates around , then,
saw it in half in the slot and go find another bolt.
or toss the whole thing and get another stem and bar.
the aluminum handlebar and aluminum in general,
is not infinite in its service life , quite the contrary.
You're right, my browser doesn't always open photos unless I do so manually. I didn't know there was a photo, and the description of the problem sounded like the stem bolt, not the HB pinch bolt.
If you ditch that bolt (I'd cut it with an angle grinder), you should be able to replace it with an allen head bolt.
11-14-10, 12:43 PM
The stem looks like it might be one of those old AVA "death stems." If so you may want to consider replacing it prophylacticly. Be aware your Peugeot may have a metric diameter steer tube (25mm vs 1"), so a replacement stem may require a little sanding in order to fit.
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