I figured someone must have posted an article about this somewhere but I'm having a hell of a time finding it. Here's how I do it, but use at your own risk, I'm not responsible if you knock a braze-on loose.

Someone had a Peug MTB fixie conversion with campy bottom-end listed on the local CL. It was in rough shape but decent parts. As with most fixies I pick up on the cheap, the top tube guides were smashed down from hard riding with no rear brake cable routed.

Click the images below for larger versions.

I normally insert, tap and wiggle a tapered punch to get things back into shape but the cable guide on this thing was totally smashed down. I took a small flathead screwdriver to initially open it up gently without creasing so I could get my preferred tap in.

Pic after prying open with small flathead, note the crease on the rear one, we're going to take that out gently:



If you're dealing with really nice paint, you could toss two rounds of blue painters tape to pad the frame on each side of the guide. This frame already has its problems, so I'm going without. I work from both sides, starting on one, tapping the tapered punch in lightly with a hammer until initial expansion is done.



Once the initial expansion is done, you can rock back/forth between the drive side and non-drive side of the bike if it's slanted towards one side or the other. Usually a few brisk taps will get it open. Once you get one side looking decent, move to the other. If necessary, you can take a wooden wedge through the gap the fore/aft guide pieces (if applicable) should they lean towards one another.

Here's my end result after doing both sides. Total work time: 5. All three were done in less than 10 minutes, this one was just exceptionally bad.



I don't claim to do anything perfect or by the book. This is just the easiest way I've found. Any tapered punch will work. There's probably a tool out there to do this "properly", but I like this punch because it's easy to work with and offers decent leverage to manipulate the braze-on.

Good job, restoring tips are always welcome!

I just did this a day or two ago, to a mid eighties Bianchi. One word of caution - don't pry to hard on the eyelet. It just might snap right off. This happened to me once, I learned, and now I share what I learned back then.

This is how Mr. Mouse, Micky to his friends, managed to damage the eyelet...

Nice tutorial. Thanks!

That tapered punch, should someone wish to buy one at their local hardware store, is called a "nail set." They come in a variety of sizes.

Brent

I love seeing these tips also. We had this happen to a bike on a trainer. Problem was sweat actually rusted it away. Time to braze I guess.

You can't say he wasn't creative...and such an off label use of a draw nut, too!

A mandrel (as in, a metal forming tool) would be the tool to do that kind of work. Rather than being sized at the minor diameter, as a punch, it is sized, as a tapered reamer, from x-y. A punch could be considered a mandrel, so I would say that is the 'right' tool.

Yep, sorry for using "punch" generically. If anyone wanted to buy, it's a Stanley nail set, and it's only $3 USD on Amazon.

I have a variety of little bits here and there I use for stuff like this. I like the nail set more than the other smooth tapered punch you see here because the texture on the nail set makes it easier to manipulate the petal when tapped in. The threaded thing in the middle is out of an Independent skateboard truck from the 80s