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 Post subject: Marin stem removal
PostPosted: Wed Feb 20, 2013 1:52 am 
Retro Guru

Joined: Sun Sep 23, 2012 10:00 pm
Posts: 474
Location: Chobham. Surrey.
Picked up a 91 Marin Pine Mountain a while back. It's been sitting in the bike sheds at work since then until i had time to do something with it.

It's condition was a little unloved but it was very original even down to orginal Rockstars on the original rims.

Started the big strip down tonight and all the areas I normally struggle with came out without too much effort.

Got to the front of the bike and problems started. Removed the stem bolt nice and easy, went to twist the hqndlebars to remove them and they wouldn't budge. Steering moves freely but cant remove the forks as I cant remove the stem.

Looking down the hole it looks like the shim from the end of the stem bolt is stuck in the tube. Put a drift in there and hammered it out but nothing.

Can't help feeling i am missing something very obvious. Or has the stem bolt shim fused to the down tube?

Has anyone else experienced this kind of seizure? If so what did you do?

I could try heat but the frame is in nice Zolatone so I am reluctant to jeopardise that.

Any advice gratefully received.

Thanks

Mark


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 Post subject: Re: Marin stem removal
PostPosted: Wed Feb 20, 2013 3:39 am 
Retro Guru
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Joined: Fri Jan 13, 2012 2:28 am
Posts: 1057
Location: Near Gatwick
Hammering a drift in from underneath isn't going to loosen it. Stick the bolt back in
and hammer the bolt down, stick it in so the thread is engaged fully.


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 Post subject: Re: Marin stem removal
PostPosted: Wed Feb 20, 2013 4:18 pm 
Retro Guru
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Joined: Mon Aug 01, 2011 7:17 am
Posts: 1219
Location: Northants
I had a similar problem also on a pine Mtn bud... I soaked it in Plusgas over night and that helped a lot.


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 Post subject: Re: Marin stem removal
PostPosted: Wed Feb 20, 2013 5:32 pm 
eBay Outing Master
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Joined: Sat Nov 21, 2009 3:53 pm
Posts: 8000
agree..bolt back on and into the wedge a good few threads/turns..a few over night soaks with the plusgas


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 Post subject: Re: Marin stem removal
PostPosted: Wed Feb 20, 2013 6:08 pm 
retrobike rider
retrobike rider

Joined: Thu Apr 17, 2008 1:24 am
Posts: 7562
Location: Manchester
If you have no plusgas then Coke will work if it is a steel fork. No idea about aluminium though.


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 Post subject: Re: Marin stem removal
PostPosted: Wed Feb 20, 2013 6:16 pm 
retrobike rider
retrobike rider

Joined: Thu Apr 17, 2008 1:24 am
Posts: 7562
Location: Manchester
Sheldon Brown wrote:
For steel seatposts stuck into steel frames, where the problem is often caused by rust, penetrating oil can do wonders. If you don't have real penetrating oil, any light lubricating oil is better than nothing, but penetrating oil is made specifically for this purpose, and you should buy a can if you don't already have one.

Aluminum seatposts frequently become stuck by corrosion also, and penetrating oil is almost useless against aluminum oxide. Fortunately, aluminum oxide can be dissolved like magic by using ammonia. [Jobst Brandt doesn't think this works, because the ammonia won't penetrate -- see his comments on stuck handlebar stems. Drano drain cleaner in water also dissolves aluminum oxide. Leaving the frame upside down with the seatpost soaking in one of these liquids may possibly free the seatpost. With the frame upside down, you might also run liquid down from inside as described in additional suggestions.-- John Allen]

[Temperature-differential method, which is applicable to any seatpost material: Buy dry ice (solid carbon dioxide, which melts at -78.5° C (- 108° F). If you have access to laboratory supplies, you might also use liquid nitrogen, which is even colder, though its cooling effect is not as great because it boils, forming a shield of gas around itself. Ordinary water ice also might work. Remove the bottom-bracket parts, cork the top of the seatpost if it is open, and with the frame upside-down and a saddle attached to the seatpost, drop chips of (dry) ice or pour liquid nitrogen down the seat tube into the seatpost. Then hold the saddle down on the floor with your feet and twist the frame. You may also warm the seat tube by pouring hot water onto its outside. Wear winter gloves, boots and socks. Do not touch dry ice, the seatpost or other parts chilled by dry ice or liquid nitrogen. I thank John Newgard for this suggestion. Sheldon's original suggestion follows -- John Allen]


Drain cleaner isn't ideal as it will remove anodizing on the stem wedge, assuming your going to re-use it.


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 Post subject: Re: Marin stem removal
PostPosted: Wed Feb 20, 2013 7:48 pm 
iconoclassic best in show
iconoclassic best in show
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Joined: Mon Feb 28, 2011 12:30 am
Posts: 2417
Location: Derby
I don't get it why did you unscrew the stem bolt ?
The bolt stays attached to the aluminium wedge , you just back the bolt off and then give the bolt a brisk tap with a hammer and ....hey presto it comes loose
The stem itself shouldn't get rusted to the steerer tube as there is a paint finish on the inserted portion but I guess if it has been scratched up then the Plusgas is a good solution.


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 Post subject: Re: Marin stem removal
PostPosted: Fri Feb 22, 2013 1:51 am 
Retro Guru

Joined: Sun Sep 23, 2012 10:00 pm
Posts: 474
Location: Chobham. Surrey.
Soaked it overnight. Gave it a wack and all done now.

Many thanks folks


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 Post subject: Re: Marin stem removal
PostPosted: Fri Feb 22, 2013 12:00 pm 
retrobike rider
retrobike rider
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Joined: Wed Mar 03, 2010 11:59 am
Posts: 4437
Location: Near Southampton
Ahh the faithful "give it a whack" comes good again! Lets see some pics soon Mark!


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