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Threaded headset Top race cup won't unscrew

Old 11-19-19, 03:17 PM
  #1  
alexnagui
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Threaded headset Top race cup won't unscrew

Trying to remove the headset from a 70's french bike. I can't unscrew that adjustable race cup, it is pretty stuck. I already tried soaking it in penetrating oil for two days or so but it still won't get loose.




Well, it seems that the stem was not installed to its minimum insertion position and probably overtightened at some point in the past which deformed the steerer tube. I can feel it with my finger on the inside of the steerer tube more or less at the level were the top race cup is sitting. So I guess that this is causing the problem, the race cup has got clamped by deformed steerer tube.

Do I need to destroy the headset now? What would you do?
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Old 11-19-19, 03:49 PM
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First post some more photos, unblurred this time, from multiple angles and well lit. Then decide which part(s) you want to salvage -- if any.
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Old 11-19-19, 04:04 PM
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Is it possible that the raised ring atop the threaded race is a separate part? I would expect there to be a keyed washer in that position and if the key is not lined up with the keyway in the steerer, then it will be almost impossible to unscrew the threaded race. The solution, if I am correct, is to use some channel lock pliers to forcefully turn the washer to align the key with the keyway.
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Old 11-19-19, 04:41 PM
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What is that, sticking up through an opening of that top washer? It's in the left front of the pic, and hard to miss. 🤔

Just guessing here, but I bet it either pulls outwards, to release a catch, or might be threaded. 🤔
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Old 11-19-19, 05:11 PM
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Either way if it's French threaded try not to destroy it.
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Old 11-19-19, 05:37 PM
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Originally Posted by stardognine View Post
What is that, sticking up through an opening of that top washer? It's in the left front of the pic, and hard to miss. ��

Just guessing here, but I bet it either pulls outwards, to release a catch, or might be threaded. ��
It does look like something deformed the threads by whatever that is sticking up thru the top "collar"--wonder if it might have been caused by a wrench used to turn the part sticking up and out of the collar? Just a guess.
Found this on Sheldon Brown-could be it: "Keyed Washer

A keyed washer is a washer with a special-shaped hole that fits over a special shaft. It can slide, but not turn. The usual set up is to have a groove in the axle or shaft. A washer's hole will have a small tang that fits into the groove. This is almost always used in headset and pedal bearings. It used to be common in hub bearings as well, but has fallen out of favor for that application.

Another type of keyed washer fits a shaft that is round but has one (or more) flat side(s). French forks usually use this system, with a simple filed flat on the back of the steerer.

Last edited by freeranger; 11-19-19 at 05:45 PM.
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Old 11-19-19, 10:57 PM
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The keyed washer is already removed. You can see how the setup worked in the video, below, at about 2:02. The washer had an internal key that went into the slot you see in the steerer tube. So the washer wouldn't turn. The washer itself had a number of holes (one about every 10°) drilled into it. In the picture above you see a pin sticking out of the race. That pin would insert in one of the washer holes, preventing it from rotating.

You probably want to save the race (with pin intact!) and the washer and the fork. The standard ways are
1) penetrating oil like Kroil. If you don't care about the paint, a 50/50 mixture of ATF and acetone is said to work best.
2) If oil doesn't work, you could try heat. Heat the joint, carefully, with a torch (standard propane is probably fine). Easy does it.


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Old 11-20-19, 12:02 AM
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Originally Posted by WizardOfBoz View Post
The keyed washer is already removed. You can see how the setup worked in the video, below, at about 2:02. The washer had an internal key that went into the slot you see in the steerer tube. So the washer wouldn't turn. The washer itself had a number of holes (one about every 10°) drilled into it. In the picture above you see a pin sticking out of the race. That pin would insert in one of the washer holes, preventing it from rotating.

You probably want to save the race (with pin intact!) and the washer and the fork. The standard ways are
1) penetrating oil like Kroil. If you don't care about the paint, a 50/50 mixture of ATF and acetone is said to work best.
2) If oil doesn't work, you could try heat. Heat the joint, carefully, with a torch (standard propane is probably fine). Easy does it.


https://www.youtube.com/watch?v=9jHU2mosbD0
Thanks for the tips! I am gonna soak it in penetrating oil for a week or so and try again.
Heating it should definitely work but I don't own a torch. I tried it with boiling water with no success.
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Old 11-20-19, 12:06 AM
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Originally Posted by dedhed View Post
Either way if it's French threaded try not to destroy it.
Yes, it's French and I would like to save it.
But I hate the threaded race with no flats for a proper wrench.
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Old 11-20-19, 07:41 AM
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Originally Posted by alexnagui View Post
Yes, it's French and I would like to save it.
But I hate the threaded race with no flats for a proper wrench.
A strap wrench should do the trick. 5 bucks at Harbor Freight.
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Old 11-20-19, 08:02 AM
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So what is that protruding nub of metal? And was it designed to do? Was there another washer under the keyed washer with a small hole to match the nub?
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Old 11-20-19, 08:22 AM
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Originally Posted by mitchmellow62 View Post
So what is that protruding nub of metal? And was it designed to do? Was there another washer under the keyed washer with a small hole to match the nub?
Check out the video I posted above, at about the 2"02' mark. And the pic of the lockwasher, below.

The lock washer lays on top of that race with the pin. The washer has an internal key that engages the steer tube, so that the lockwasher doesn't turn. The washer has 36 holes drilled through it at 10°increments. You preload the race, drop the washer onto the steerer tube and the protruding pin goes through one of the 36 lockwasher holes (with some tweaking, no doubt). This keeps the race from turning.

Given that other, high-quality setups got by with a keyed washer alone, and that the pin/perforated washer setup limits the precision with which one can preload, one asks why the perforated washer and pin was needed. Ingenious, but perhaps engineering overkill? All arguments about engineering elegance aside, I think its an amusing idea.


Last edited by WizardOfBoz; 11-20-19 at 10:08 AM.
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Old 11-20-19, 08:30 AM
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Originally Posted by alexnagui View Post
Thanks for the tips! I am gonna soak it in penetrating oil for a week or so and try again.
Heating it should definitely work but I don't own a torch. I tried it with boiling water with no success.
An industrial heat gun (or even a hair dryer) might work. BTW, "ATF" stands for "Automatic Transmission Fluid". In some tests that were run, half and half ATF and acetone worked better than penetrating oils like Kroil and PB Blaster (two products available in the US). But acetone will strip that old paint.

I agree that having no wrench flats was a bad design. As suggested, a strap wrench will give you a better purchase (it will grab better). I find it useful to alternate between tightening and loosening. If you can get the race rotating even a little, it allows that penetrating oil to get in their better.

Veel geluk!

Postscript: If you use a heat gun, a hair dryer, or a torch, make sure any acetone or oil has been removed pretty completely!

Last edited by WizardOfBoz; 11-20-19 at 10:08 AM.
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Old 11-20-19, 09:58 AM
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Originally Posted by Moe Zhoost View Post
A strap wrench should do the trick. 5 bucks at Harbor Freight.
It's basically a rubber band, isn't it? I am using 30 cm long water pump pliers and still can't get enough leverage so I don't think that a strap wrench would make any difference. But thanks for advice, didn't know about such a wrench.
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Old 11-20-19, 10:11 AM
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Originally Posted by alexnagui View Post
...
Well, it seems that the stem was not installed to its minimum insertion position and probably overtightened at some point in the past which deformed the steerer tube. I can feel it with my finger on the inside of the steerer tube more or less at the level were the top race cup is sitting. So I guess that this is causing the problem, the race cup has got clamped by deformed steerer tube.

Do I need to destroy the headset now? What would you do?
If that is the case then penetrating oil and brute force are not the solution. Seek out an expert metal worker. The right one will salvage both the headset and the fork.
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Old 11-20-19, 10:28 AM
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Originally Posted by alexnagui View Post
It's basically a rubber band, isn't it? I am using 30 cm long water pump pliers and still can't get enough leverage so I don't think that a strap wrench would make any difference. But thanks for advice, didn't know about such a wrench.
I'm not sure what the straps on the Harbor Freight ones are, but mine is a woven low-stretch rubberized fiber strap. As it tightens, it grips the whole circumference allowing leverage without damage. Anyhow if your pliers haven't broken it loose, I doubt that a strap wrench would do much either.

How are you holding the fork while attempting to loosen the race? I'd advise clamping it at the fork crown because, with the amount of torque you might be applying, it would be very easy to bend the fork stays if you're just holding the fork with a mounted wheel.
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Old 11-20-19, 10:51 AM
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.
...if I were having a problem like this one, I would use a 50/50 mix of acetone and ATF as my penetrating oil, and one of these Hozan pliers, which work well for that type of headset. I would also set up the frame and fork in a stand with the fork ends clamped in a fork vise. Which in turn would be clamped in some sort of vise table like the ones sold as "Black and Decker Work Mate"



But it would probably be cheaper and easier for you to just buy yourself a MAPP gas torch at the Home Depot and loosen it with penetrant and heat.

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Old 11-20-19, 11:07 AM
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Originally Posted by WizardOfBoz View Post
Veel geluk!
An unexpected occurrence of dutchiness.
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Old 11-20-19, 11:20 AM
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Originally Posted by WizardOfBoz View Post
An industrial heat gun (or even a hair dryer) might work. BTW, "ATF" stands for "Automatic Transmission Fluid". In some tests that were run, half and half ATF and acetone worked better than penetrating oils like Kroil and PB Blaster (two products available in the US). But acetone will strip that old paint.

I agree that having no wrench flats was a bad design. As suggested, a strap wrench will give you a better purchase (it will grab better). I find it useful to alternate between tightening and loosening. If you can get the race rotating even a little, it allows that penetrating oil to get in their better.

Veel geluk!

Postscript: If you use a heat gun, a hair dryer, or a torch, make sure any acetone or oil has been removed pretty completely!
I don't care about the paint that much, but first I will see if penetrating oil helps. As I said before, it didn't help much after 2 days of soaking the headset in it though.

The race won't move at all which is strange given the fact that the headset is kinda loose. It's been like that since I got the bike. That's why I actually thought that there might be something else involved. The deformation of the steerer tube seems like a logical explanation to me.

And yeah, dankjewel!
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Old 11-20-19, 11:22 AM
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Originally Posted by AnkleWork View Post
If that is the case then penetrating oil and brute force are not the solution. Seek out an expert metal worker. The right one will salvage both the headset and the fork.
So what will be the right procedure to tackle this in order to salvage the headset and the fork? Just curious how it should be done
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Old 11-20-19, 11:23 AM
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Anklework's point, that if the fork tube is distorted you may need more expert help, is a good one. If you can't get the race off with penetrant, heat, and force, then you have to consider alternate methods. Typically a bearing race is harder and stronger than the steer tube, and hence if overtightened its the tube, not the race, that is distorted. So this may involve cutting the fork steer tube (like with an abrasive disc in a small hand-held rotary tool). Not such a bad thing if the models was common - ebay will have spares. But if the bike is rare, and worthy, you may end up having a new steerer welded or (with sleeves) brazed on

I suspect that with diligence, heat, penetrant, working the thing back and forth, and having the fork braced well, you should be able to get it off.
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Old 11-20-19, 11:26 AM
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Originally Posted by Moe Zhoost View Post
I'm not sure what the straps on the Harbor Freight ones are, but mine is a woven low-stretch rubberized fiber strap. As it tightens, it grips the whole circumference allowing leverage without damage. Anyhow if your pliers haven't broken it loose, I doubt that a strap wrench would do much either.

How are you holding the fork while attempting to loosen the race? I'd advise clamping it at the fork crown because, with the amount of torque you might be applying, it would be very easy to bend the fork stays if you're just holding the fork with a mounted wheel.
I was holding the fork at the fork crown with one hand and trying to unscrew the thing with the pliers in my other hand. Which is quite akward and doesn't allow me to apply a lot of leverage. Clamping the fork crown should be a better approach indeed.
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Old 11-20-19, 11:28 AM
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Originally Posted by WizardOfBoz View Post
BTW, "ATF" stands for "Automatic Transmission Fluid". In some tests that were run, half and half ATF and acetone worked better than penetrating oils like Kroil and PB Blaster (two products available in the US).
...all true. The stuff is magical.

Originally Posted by WizardOfBoz View Post
Postscript: If you use a heat gun, a hair dryer, or a torch, make sure any acetone or oil has been removed pretty completely!
...I have done this regularly using the ATF/acetone mix and a MAPP gas torch. The amount of acetone involved is pretty minimal and it flames off quickly with no adverse effects I can observe. And the flames that arise from the spot you're trying to knock loose are a visual encouragement that surely something must be happening.
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Old 11-20-19, 11:28 AM
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Originally Posted by 3alarmer View Post
.
...if I were having a problem like this one, I would use a 50/50 mix of acetone and ATF as my penetrating oil, and one of these Hozan pliers, which work well for that type of headset. I would also set up the frame and fork in a stand with the fork ends clamped in a fork vise. Which in turn would be clamped in some sort of vise table like the ones sold as "Black and Decker Work Mate"



But it would probably be cheaper and easier for you to just buy yourself a MAPP gas torch at the Home Depot and loosen it with penetrant and heat.

That's a proper setup! And those Hozan pliers look quite handy for the job!
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Old 11-20-19, 11:31 AM
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Originally Posted by alexnagui View Post
I was holding the fork at the fork crown with one hand and trying to unscrew the thing with the pliers in my other hand. Which is quite akward and doesn't allow me to apply a lot of leverage. Clamping the fork crown should be a better approach indeed.
...the only downside to grabbing the crown in a vise is possible cosmetic damage, which it would appear is less important to you in this case.
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