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Dura Ace 7400 stem, stuck.

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Dura Ace 7400 stem, stuck.

Old 06-12-19, 12:24 PM
  #1  
merziac
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Dura Ace 7400 stem, stuck.

These seem to be as much of a PITA as they are cool. This one is stuck pretty good, all the screws turn just fine but it isn't budging. They are a crappy design IMHO, everything is trapped by set screws so the cone wont come out the bottom, Shimano says DON'T tap on the wrench/bolt so WTF.

It's been soaking with PB blaster and Marvel Mystery oil for 2-3 days.

Any words of wisdom will be much appreciated, TIA
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Old 06-12-19, 12:34 PM
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I have never owned one , but it looks like if you can get the cover screw off you could tap on the tighten up screw with a proper drift punch and the cone will move down (first loosen up the bolt a few turns , sorry if you knew that ) . If it's stuck onto the steerer tube then keep up with the PB Blaster from the top and the bottom . I just went through this with a 3TTT stem , finally after about 2 wks. I got it .
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Old 06-12-19, 03:31 PM
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Originally Posted by markwesti View Post
I have never owned one , but it looks like if you can get the cover screw off you could tap on the tighten up screw with a proper drift punch and the cone will move down (first loosen up the bolt a few turns , sorry if you knew that ) . If it's stuck onto the steerer tube then keep up with the PB Blaster from the top and the bottom . I just went through this with a 3TTT stem , finally after about 2 wks. I got it .
The threaded shaft is always engaged with the cone and the stem, it is never free, your pounding on the threads no matter what and the cone is held in by set screws so you can't get it out the bottom either. Shimano tells us no tapping.
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Old 06-12-19, 04:50 PM
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I own a few of these stems and havent had any get stuck.

I would twist and turn the whole stem when its inserted in the steer tube. Then pull.
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Old 06-12-19, 05:55 PM
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Originally Posted by malcala622 View Post
I own a few of these stems and havent had any get stuck.

I would twist and turn the whole stem when its inserted in the steer tube. Then pull.
It doesn't budge or move at all, not even sure the cone is loosening.
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Old 06-12-19, 06:18 PM
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Give it a tap, what could possibly go wrong?
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Old 06-12-19, 07:11 PM
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Originally Posted by P!N20 View Post
Give it a tap, what could possibly go wrong?
Already did, more than I should have, no bueno.

Shimano says do not do it.
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Old 06-12-19, 07:24 PM
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Originally Posted by merziac View Post

Shimano says do not do it.
Well, look how well their advice has turned out so far with that stem?

Stuck.
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Old 06-12-19, 08:47 PM
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How about pouring a little Krud Kutter rust remover into the steerer tube. Might just break up that cone on inner steering tube connection.
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Old 06-12-19, 10:05 PM
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Originally Posted by Manny66 View Post
How about pouring a little Krud Kutter rust remover into the steerer tube. Might just break up that cone on inner steering tube connection.
Thought about that and may do it, don't think cone is stuck, going to try and figure that out, not that it matters, unless it magically becomes unstuck, I suck.
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Old 06-12-19, 10:12 PM
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Originally Posted by The Golden Boy View Post
Well, look how well their advice has turned out so far with that stem?

Stuck.
Yep, right you are. Still going to proceed with extreme caution until I fully understand how this works, saving this is paramount for now.
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Old 06-12-19, 10:18 PM
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The ultegra 6400 and DA 7400 have the same quill + nut wedge design. Seems the nut is seized and isnt allowing the wedge the drop and free up the stem. I'd try a long ratchet from the fork bottom entry and loosen it from there.
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Old 06-12-19, 10:56 PM
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Originally Posted by malcala622 View Post
The ultegra 6400 and DA 7400 have the same quill + nut wedge design. Seems the nut is seized and isnt allowing the wedge the drop and free up the stem. I'd try a long ratchet from the fork bottom entry and loosen it from there.
They don't though? HS-7400 has a cone like all the other DA stems, and HS-6400 has a wedge like all the other 600 stems. 600 stems have a nut on the bottom of the wedge, DA stems have set screws that are perpendicular and prevent the cone from rotating.

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Old 06-12-19, 11:05 PM
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Originally Posted by merziac View Post
They are a crappy design IMHO, everything is trapped by set screws so the cone wont come out the bottom
It seems to be that Shimano stems are a better design in this regard. Tapping should be completely unnecessary because turning the screw should force the expander out.

Last edited by Kuromori; 06-12-19 at 11:14 PM.
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Old 06-12-19, 11:21 PM
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Originally Posted by Kuromori View Post
They don't though? HS-7400 has a cone like all the other DA stems, and HS-6400 has a wedge like all the other 600 stems. 600 stems have a nut on the bottom of the wedge, DA stems have set screws that are perpendicular and prevent the cone from rotating.
You are correct. My bad. I was looking at an AX 600 thinking it was DA.

OP may have to tie the stem and fork to 2 tractors and have them pull in opposites directions.
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Old 06-13-19, 12:53 AM
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Originally Posted by Kuromori View Post
It seems to be that Shimano stems are a better design in this regard. Tapping should be completely unnecessary because turning the screw should force the expander out.
Maybe in a perfect world, but even the factory manual says to stop turning the wrench when it becomes hard to turn again after cracking it loose and loosening it. I don't think it is designed to force the cone out except to nudge it loose when all is perfect and its waiting to slide right out.

Here's the manual, can't really read it though.


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Old 06-13-19, 04:36 AM
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I don't have one in front of me, but if you were able to give the bolt a few turns it should already be disengaged. I believe the bolt has 2 different thread pitches which are both LH threads. When you turn CCW, the bolt moves down through the stem with the coarse pitch, and the cone moves up on the fine pitch, although the cone moves down more than it moves up due to the difference in pitches. Keep turning the bolt CCW, and the cone keeps moving up the bolt, but down out of the stem, until it runs out of fine threads.

As Macala says, I think at this point it's just the stem stuck to the steerer, not the expander being stuck, so time to use chemicals and force.
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Old 06-13-19, 05:50 AM
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You people are missing the simplest solution.
Send the bike to me. Problem solved.
Why so complicated?

Otherwise:
Turn upside down.
PB Blaster 2 days in a row.
Cover with a blanket.

Do the hissy-fit &^%$# bike dance.
Drink something cold and refreshing.
Smile at complete strangers.
Wait 4 days.
Give 10.00 to charity.
Ride 27.34 miles.
Wait 2 days.

Lather, Rinse, Repeat.

That sucker will come right out.
You simply have to honor the mojo.
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Old 06-13-19, 06:41 AM
  #19  
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I was trying to visualize the wedge design being described then I came across that exact part while perusing eBay this morning: https://rover.ebay.com/rover/0/0/0?m...2F372652115917
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Old 06-17-19, 02:00 AM
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Originally Posted by RobbieTunes View Post
You people are missing the simplest solution.
Send the bike to me. Problem solved.
Why so complicated?

Otherwise:
Turn upside down.
PB Blaster 2 days in a row.
Cover with a blanket.

Do the hissy-fit &^%$# bike dance.
Drink something cold and refreshing.
Smile at complete strangers.
Wait 4 days.
Give 10.00 to charity.
Ride 27.34 miles.
Wait 2 days.

Lather, Rinse, Repeat.

That sucker will come right out.
You simply have to honor the mojo.
Absolutely brilliant! Didn't even have to do any of the hard parts, still going to wait another day or two, should come right out.

As always, patience is key, soak, lather, rinse, repeat, change fluid, wait and Voila!

I think the MM Oil helped as well.
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