Hi
The two ears of the integrated seatpost clamp on my bike is little deformed because of the improper torque applied to tighten the binder bolt in the past. They are just getting too close with each other,so the bolt holes on the two sides are not paralleled and a new bolt can not pass through.
Any idea on how to solve the problem?
Thank you in advance for sharing your ideas.

It appears that a smaller seatpost may have been clamped in, or a normal seatpost was over tightened. Examine the slot in the seat tube - if it is not even from top to bottom, probably a smaller seatpost was used. If it is even from top to bottom, probably over tightened. That's my best guess from the photo.

Edit
It looks like the right side is deformed.

Yup. Put a big blade screwdriver between the ears and twist it open far enough for the bolt to pass easily.

Hi. Thanks for the reply. The slot looks a little not even. The Bottom is slightly larger than the top. If it's the problem caused by the wrong size of the seatpost, I will have it swapped.

What [MENTION=173992]non-fixie[/MENTION] said. If you can spread the slot enough to get a bolt through, that may help the deformation of the right side and give an accurate measure of the seat post that is needed.

Just as a back-up in case something goes wrong, I have a tandem where one of these clamps had been broken off before I acquired the bike, and I was able to remove both clamps with a dremel tool and replace them with a separate clamp around the top of the seat tube that worked to get the seatpost tight.

-Will

Hi. It worked. Thank you very much. [MENTION=173992]non-fixie[/MENTION]. With the screwdriver prying open a bit the ears, bolt is in place now.

But with the deformed ear,the locknut does not engage well with it.
There is a fairly big gap at the bottom of the contacting surface.
It's already been 60-70% tightened. I'd like to get some advice before I proceed. Could I have it fully tightened?


Hi. [MENTION=336348]dweenk[/MENTION]. I have accessed the frame information and checked the seat post. It's the correct size for the seat tube.

Thanks for the back-up idea. [MENTION=1290]will[/MENTION]. It really works for some frames. But there is very limited space on my frame for mounting a separate clamp. Braze welding new ears maybe the back-up for this frame if something goes wrong. (I hope that will not happen&#128517.

The trick with pinch bolts in general is to tighten them just enough to keep the pinched object - in this case the seat post - from slipping. So if the post doesn't move, you're good.

If the seat post is the right size, the deformation is likely to be from a previous owner being overzealous.

It looks like the front and top of the right ear are about where it needs to be. The rear and lower part is the most deformed.


Disclaimer: If it was mine AND I was in total "git her done" mode (requires about 3 IPAs), I would try to pry that ear back while the bolt is in place. Without IPA influence, I'd let it be as long as the seat post was stable.