alexnagui

The bike is not rare (it's Peugeot PR10) and not a keeper actually so even changing the fork won't be that bad. I hope it won't be needed though. I might bring it to my LBS where they have a torch, I believe, and could clamp the fork crown properly.

alexnagui

yeah, that wouldn't be a big problem

AnkleWork

First characterize the problem, something that's impossible to do remotely with a poor photo. You know, careful measurements, observations and asking the right questions. Is the steerer ovalized? ...how much? etc. Maybe try tightening the race on the bearings. If the threads turn easier that way then the way forward becomes much clearer. Then devise a procedure.

Some here still seem unclear on the concept. If the threads are bound due to distortion of the parts then penetrating oil will do nothing and brute force will cause more damage.

WizardOfBoz

Agree with Anklework. If the cup is now loose, you may want to see if you can tighten it a bit to inspect the threads. And to get lubricant into the threads. But if the steer tube is ovalized and the threads are messed up you may end up sawing off the top tubes from the inside with an abrasive disk and a hand-held or flexible shaft tool. For a common bike, easy enough to find a cheap replacment fork.

Miele Man

I think that unless you can anchor the frame so that you have two hands free to work on the headset, you're looking at a two person job. I'd get a buddy to hold the bike and I'd try using a pipe wrench to turn that headset part. However, I'd grease all the threads above that headset part to reduce friction as much as possible. Also, as someone else suggested, if you can thread that headset part onto the fork even a bit more that might help you get lubricant (grease) onto all the threads that the headset part will be bearing against as you loosen it.

If there is a picnic table near you I' strap the bike on its side to the top of the table. Then you can apply LOTS of torque to that headset part without much worry about damaging the fork or twisting the frame. I've done that with stubborn headset parts in the past as well as doing that to loosen really stubborn aluminium seatposts in a steel frame.

Good luck and please let us know how you get that part off.

Cheers

3alarmer 

...this all sounds very mysterious. Assuming that the steerer is, indeed. slightly expanded because of some user error with the stem, what exactly do you envision as the "damage"? There's no room to get a fork treading die on there, if it is slightly expanded (I have personally not witnessed "ovalized", but I guess all things are possible...it seems like it would take a lot of force to ovalize the steerer on a lower end Peugeot), where is the harm in using brute force to twist off the threaded headset race, recutting the threads a little deeper and rounder in the process ?

As long as we're guessing, let's guess that there is no distortion (the case in the majority of old bikes encountered), or minor distortion. Regardless, I'm at a loss to see where going at the thing with some vigor and a positive attitude is going to cause more damage. What am I missing ? If the fork's a goner (which it will be if you cut the steerer), then replacement ought to be done with a standard threaded fork anyway, for ease in sourcing headsets.


What's the mysterious "procedure" that will solve this with finesse instead of a bigger hammer ?

AnkleWork

You read funny, but you help prove the point that many in this forum can only imagine the most brutal methods. As for the mystery, the OP does not seem inclined to reveal more.

reconnaissance

Gentlemen - that pin is the culprit. Remove the pin and it will come free.

3alarmer 

...you had another post where it was too much trouble to disagree. it was some poor shmuck who had fresh paint on his frame, and you were absolutely certain that simply running a set of taps through the BB threads would be the end of life on earth as we know it. "Taps remove metal", you said, and then went on to suggest some other unnamed method that ought to do the trick (excluding power brushing because of "thread embrittlement". Again, no help at all to the guy with the problem, just more "everyone here in this forum is an unsophisticated mechanical caveman."

Used appropriately and with even a moderately skilled hand, the piloted BB tap is, indeed, the most effective means of accomplishing that task. Threaded into the existing threads properly, it removes very little metal as it goes merrily on it's way taking out paint, rust, and other gunk. While certainly true that it's not something to do routinely, I can't think of many secret alternatives that will do as good a job as quickly and efficiently. certainly a freshly painted frame is not something you want to slop solvent around in. And I'm dubious that a thread file will take out less metal than the taps, used appropriately.

I just think that you have a very mysterious approach to all this. If I spent as much time as you do here imagining additional problems that I might incur on a repair job, It would take me days to sort it all out before I might accomplish the simplest of tasks...like that one with paint in the threads. If you think this forum can only imagine the most brutal methods, you ought to posit the alternatives, instead of making up unspoken alternatives. Unless I'm missing something, the majority of the contributors here are trying to suggest helpful alternatives for repair.

Once more, what's the sophisticate's method for addressing this problem with the headset ?

3alarmer 

...that pin is a locking pin for the washer/spacer above the race, which has holes in it so you can select one, drop it on, and it will more or less remain in position while you tighten the headset locknut. It's a French thing.

WizardOfBoz

I don't believe that this is the case. The pin (I think) rotates with the threaded race. The pin goes into one of the holes on the perforated washer (see pic above, and watch the video - they don't pull the pin). So the key on the washer keeps the washer from rotating wrt the steerer tube, and the pin on the race keeps the race from rotating. The pin doesn't affect the rotation of the race.

If the washer is still installed then it needs to be removed. The OP can enlighten us if he has'nt pulled the washer. But I don't see holes around the periphery, and the pin is projecting out a lot (if the washer was installed it would be flush with the end of the washer. So I think he's already got it off.

I am willing to be corrected, but to me it looks like in no scenario would you want to pull the pin out.

freeranger

Maybe try packing the steerer tube with ice (dry ice would be best) to see if it would contract it enough to get the top race cup starting to unthread?

AnkleWork

And what do you claim is the problem, exactly?

3alarmer 

...attitude. It's an attitude problem.

AnkleWork

Yet again, thank you for proving my point.

stardognine

I'm not familiar with this type of headset at all, so you might very well be 100% correct. 🙂 But it seems to me, that if the innards are full of rust, that could very well keep things from moving right. 🤔 I'd be shooting something in that pin opening, just in case that does some good.

3alarmer 

...you are quite welcome. Happy to help.

WizardOfBoz

You could be right! I'd love to inspect one of these. For now, though, my hypothesis is that the pin is just sticking in a hole in the top of the race, and doesn't communicate with the threads at all. In fact, if the pin was beefier or the race less stuck, you could make a wrench by drilling a hole just a little bigger than the steerer tube in a flat piece of bar stock, and drilling a small hole to correspond to the pin. But given how stuck the race is, I think that might break the pin off.

alexnagui

Hi everyone! Sorry for not replying for a while. I admit that I hadn't provided you with proper pictures and enough information. The threads seemed to be perfectly fine, at least visually. The race didn't move at all when I tried to remove it at home.


However, I managed to take it off several hours ago. I went to my LBS where they have a proper vise which I could use. Once the fork was clamped into the vise, it was a matter of applying quite some force to remove it. But it got loose in the end!
My theory got actually approved. The steerer tube got kinda expanded that's why the race wouldn't move. The guy at the shop chased the threads with a tap so the fork should be fine to use. However, when I got home I got to think whether he used the right tap for French threading

3alarmer 

...where you are located, it's more likely he might. I think I might have the only one in my city to chase a French fork. And I have used it maybe twice. It's pretty likely he used the right one, because a French steerer from back in ancient times is of slightly different diameter...

Moe Zhoost

Well, my first thought was that he should realise that a French bike may have French threading. My second thought was that a competent mechanic would have checked with a caliper and thread pitch gauge. My third thought is that even if he used the wrong tap, he would have sensed it when he started to thread the tap on. Since a French steerer tube has a slightly smaller diameter, an English tap would have a sloppy fit, though because of the thread pitch difference, the sloppiness may have disappeared once he started cross threading. If he used the wrong tap he should buy you a new fork.

Have you checked using the race? That would tell the tale.

JohnDThompson 

French steer tubes are slightly smaller diameter than English/Italian; 25mm versus 25.4mm, so an English/Italian thread die wouldn't completely engage the threads on a French steer tube. That should make it obvious to the mechanic that the wrong die is being used.

stardognine

We need pics! Pics or it didn't happen. 😁

lapola

Miele Man

Well, if he used the wrong unit to chase the threads you might not be able to properly tighten the original headset parts; or they might feel tight but soon come loose in use.

Good luck.

Cheers