Go Back  Bike Forums > Bike Forums > Classic & Vintage
Reload this Page >

A Question for the Mechanically Inclined - The seat post rotates, but how to extract?

Notices
Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

A Question for the Mechanically Inclined - The seat post rotates, but how to extract?

Old 04-25-16, 08:29 AM
  #1  
oddjob2
Still learning
Thread Starter
 
oddjob2's Avatar
 
Join Date: May 2012
Location: North of Canada, Adirondacks
Posts: 11,617

Bikes: Still a garage full

Mentioned: 91 Post(s)
Tagged: 2 Thread(s)
Quoted: 842 Post(s)
Liked 52 Times in 33 Posts
A Question for the Mechanically Inclined - The seat post rotates, but how to extract?

Alloy post was stuck. I PB blasted and Kroiled it overnight. I tried a medium pipe wrench no luck. I hammered it down and it went into the frame further by 1/4 inch. Now with an 20" plus pipe wrench, I can spin the post, but the friction is so much, you can feel the heat build up on the 531 seat tube. It remains to be answered whether the SP is oversized, but it can be sacrificed.

Any suggestions on how to extract the SP as I spin it?

oddjob2 is offline  
Old 04-25-16, 08:34 AM
  #2  
3speedslow
Senior Member
 
3speedslow's Avatar
 
Join Date: Oct 2010
Location: Jacksonville, NC
Posts: 8,618

Bikes: A few

Mentioned: 111 Post(s)
Tagged: 0 Thread(s)
Quoted: 1699 Post(s)
Liked 492 Times in 355 Posts
hang the bike by the saddle and spin the bike while pulling it down. Or pull down on the bike while rocking it back and forth.
3speedslow is offline  
Old 04-25-16, 08:36 AM
  #3  
corrado33
Senior Member
 
Join Date: Jun 2013
Location: Bozeman
Posts: 4,094

Bikes: 199? Landshark Roadshark, 198? Mondonico Diamond, 1987 Panasonic DX-5000, 1987 Bianchi Limited, Univega... Chrome..., 1989 Schwinn Woodlands, Motobecane USA Record, Raleigh Tokul 2

Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 1129 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
You got it moving, that's the important part. A few things you could try.

I'm making the assumption that you want to replace the seatpost and that you probably ruined it with the pipe wrench/hammer.

Hold the seatpost in a vice and use the frame to twist/pull it out.

Use a large pair of vice grips and attach them to the top of the post. As you spin tap the vice grips from the bottom with a hammer so you're pulling the seatpost out while turning.

Weld a handle to the top of the seatpost and use that to twist/pull it out.

Drill a large hole perpendicular to the seatpost and stick a pry bar through it to twist/pull it out.

If you're running out of ideas, you could use a crappy threaded stem to attach to the inside of the seatpost. Make sure the wedge nut is above the frame. Use that to twist/pull on the seatpost.

Using any of the above methods, you could hold the frame between your feet while twisting/pulling on the seatpost. You'll probably hit yourself in the face once it comes out though.

This would probably be easier with two people.

Last edited by corrado33; 04-25-16 at 08:40 AM.
corrado33 is offline  
Old 04-25-16, 08:40 AM
  #4  
repechage
Senior Member
 
Join Date: Jun 2006
Posts: 15,562
Mentioned: 103 Post(s)
Tagged: 0 Thread(s)
Quoted: 1772 Post(s)
Liked 642 Times in 498 Posts
Originally Posted by oddjob2 View Post
Alloy post was stuck. I PB blasted and Kroiled it overnight. I tried a medium pipe wrench no luck. I hammered it down and it went into the frame further by 1/4 inch. Now with an 20" plus pipe wrench, I can spin the post, but the friction is so much, you can feel the heat build up on the 531 seat tube. It remains to be answered whether the SP is oversized, but it can be sacrificed.

Any suggestions on how to extract the SP as I spin it?

Time can help a bit, Kroil creeps.
I would persuade the seat lug ears open a wee bit.
More Kroil. Time.
Kroil will do nothing to the aluminum oxides, but will reduce the friction where there is room.
Then, Dry Ice. Aluminum expands and contracts faster than steel.
Use that to your advantage.
With heavy protective gloves, apply dry ice to post, wrap tight with rags, stay about 3/4" away from the frame.
10-15 minutes, the higher the ambient temp the better.
Then unwrap and see if you can get some movement.
repechage is offline  
Old 04-25-16, 08:47 AM
  #5  
mparker326
Senior Member
 
mparker326's Avatar
 
Join Date: Aug 2006
Location: Knoxville, TN
Posts: 1,978

Bikes: Schwinn Paramount P15, Fisher Montare, Proteus, Rivendell Quickbeam

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I clamp the seatpost in a vice and rotate the frame to extract.
mparker326 is offline  
Old 04-25-16, 08:57 AM
  #6  
nashvillebill
Senior Member
 
Join Date: Mar 2016
Location: Phoenix AZ
Posts: 376
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 107 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I would try a slide hammer puller, if you can find one that will fit far enough down into the seatpost then this should be easy to get out. If you can't find one, make one: get a piece of steel pipe a couple of feet long,slide it over the seat post. Drill a hole through the seat post (with a matching hole throiugh the pipe) and bolt the pipe to the seat post. On the other end of the pipe, you will screw on a cap or bolt or stop of some kind, after slipping some sort of suitable heavy weight that can slide up and down the pipe. Get someone to hold the frame down, you use the weight to apply that sudden force needed to jerk the tube out. Google "slide hammer puller" and you can probably find a video of someone using a slide hammer puller so you can get the idea, if you have never seen one in action.

Welding to the alloy will be tricky, if you try that suggestion mentioned above. Make sure the ground clamp is on the seat post, not the frame...don't want to have arcing between the frame and seat post whcih would make matters terribly worse (effectively welding the two parts together).
nashvillebill is offline  
Old 04-25-16, 09:03 AM
  #7  
satbuilder 
Senior Member
 
Join Date: May 2005
Location: Southern Maryland
Posts: 1,321

Bikes: 1969/70 Legnano Roma, 1971 Guerciotti, 1972 Cinelli SC, 1973 Bianchi Team, 173 Colnago Super, 1974 Marnati Corsa, 1974 ish Motobecane CT, 1971 Mercier 300, 1977/78 Colnago Mexico, 1982 Pinarello Italia,Tesch S-22, 1983 Peugeot Mixte

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 212 Post(s)
Liked 52 Times in 34 Posts
Do you know anybody with access to liquid nitrogen? You could spray the post and it might shrink enough to extract. If you don't want to save the post, cut it off and saw a couple slits in the remainder. Then just knock it out
satbuilder is offline  
Old 04-25-16, 09:08 AM
  #8  
corrado33
Senior Member
 
Join Date: Jun 2013
Location: Bozeman
Posts: 4,094

Bikes: 199? Landshark Roadshark, 198? Mondonico Diamond, 1987 Panasonic DX-5000, 1987 Bianchi Limited, Univega... Chrome..., 1989 Schwinn Woodlands, Motobecane USA Record, Raleigh Tokul 2

Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 1129 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by repechage View Post
Time can help a bit, Kroil creeps.
I would persuade the seat lug ears open a wee bit.
More Kroil. Time.
Kroil will do nothing to the aluminum oxides, but will reduce the friction where there is room.
Then, Dry Ice. Aluminum expands and contracts faster than steel.
Use that to your advantage.
With heavy protective gloves, apply dry ice to post, wrap tight with rags, stay about 3/4" away from the frame.
10-15 minutes, the higher the ambient temp the better.
Then unwrap and see if you can get some movement.

Both are very good ideas. Although I'd put the dry ice in the seatpost, while holding it horizontal so the dry ice doesn't go all of the way down into the frame. You could even wrap a hot rag around the frame to increase the ∆T.
corrado33 is offline  
Old 04-25-16, 09:19 AM
  #9  
jefnvk
Senior Member
 
jefnvk's Avatar
 
Join Date: Apr 2015
Location: Metro Detroit/AA
Posts: 8,212

Bikes: 2016 Novara Mazama

Mentioned: 63 Post(s)
Tagged: 0 Thread(s)
Quoted: 3634 Post(s)
Liked 73 Times in 43 Posts
You try taking the BB out, hanging the bike upside down, and oiling from the bottom? Might help to attack it in two different directions.
jefnvk is offline  
Old 04-25-16, 09:57 AM
  #10  
rootboy 
Senior Member
 
rootboy's Avatar
 
Join Date: Apr 2005
Location: Wherever
Posts: 16,756
Mentioned: 88 Post(s)
Tagged: 0 Thread(s)
Quoted: 550 Post(s)
Likes: 0
Liked 115 Times in 67 Posts
Dynamite!

I would drill a 3/8 hole straight through the post, one inch above the frame, insert a 12 inch steel rod of similar diameter through hole, and use as a "handle" with which to "unscrew" as you lift upwards. Bike frame anchored. Somehow.

Nice old Moto.
rootboy is offline  
Old 04-25-16, 10:00 AM
  #11  
lostarchitect 
incazzare.
 
lostarchitect's Avatar
 
Join Date: Mar 2010
Location: Catskills/Brooklyn, NY
Posts: 6,956

Bikes: See sig

Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 40 Post(s)
Liked 30 Times in 21 Posts
I'd try Freeze-Off before going to more drastic mechanical methods. This has worked for me in similar situations.
__________________
1964 JRJ (Bob Jackson), 1973 Wes Mason, 1974 Raleigh Gran Sport, 1986 Schwinn High Sierra, 2000ish Colian (Colin Laing), 2011 Dick Chafe, 2013 Velo Orange Pass Hunter
lostarchitect is offline  
Old 04-25-16, 10:03 AM
  #12  
simmonsgc
Senior Member
 
simmonsgc's Avatar
 
Join Date: Dec 2010
Location: NC High Country
Posts: 657
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 83 Post(s)
Liked 12 Times in 8 Posts
Re: the slide hammer idea above, here's a guy using one to extract what looks to be a stubborn post:

https://www.youtube.com/watch?v=S3ek2GeZzE0

Last edited by simmonsgc; 04-25-16 at 05:33 PM.
simmonsgc is offline  
Old 04-25-16, 11:36 AM
  #13  
Henry III
is just a real cool dude
 
Henry III's Avatar
 
Join Date: Aug 2010
Location: The Thumb, MI
Posts: 3,167
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(s)
Likes: 0
Liked 22 Times in 9 Posts
I would just swear at it and then injure myself somehow and then stuff usually feels bad and lets loose.
Henry III is offline  
Old 04-25-16, 12:16 PM
  #14  
TheGuitarFairy
Junior Member
 
Join Date: Sep 2015
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
ha! I'm such a newbie that i rarely feel qualified to post suggestions here : )

but since i had the exact same issue with the same exact same bike (including color!) i think i can contribute!

once it was very obvious i wasn't going to save the post ... i drilled a hole in post, put a big ass screw driver through post then turned bike upside down and put screw driver/post into a bench vise and proceeded to rotate frame, above!

it was a huge pita but eventually worked. frame came out of this unscathed and bike rides true.

good luck!
mike

Last edited by TheGuitarFairy; 04-25-16 at 01:55 PM.
TheGuitarFairy is offline  
Old 04-25-16, 12:59 PM
  #15  
jmeb
Senior Member
 
Join Date: Jul 2011
Location: Denver, CO
Posts: 676

Bikes: 1966 Carlton, 197X MKM, 1983 Trek 620, 1988 Schwinn High Sierra, 1995 DBR Axis Ti, 1999 Waterford, 2016 DBR Release, 2017 Surly Travelers Check

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Likes: 0
Liked 4 Times in 4 Posts
If you don't mind sacrificing the seatpost.... hack off the top of the SP with a hacksaw leaving a few inches exposed. Hacksaw down the length of the SP (i.e. inside the downtube). You'll know when you're through the soft aluminum post vs. the steel tube very quickly. Grab edge of cut with pliers, twist in and pull out.

This was the method that worked for me in a similar situation (rotation but no pulling out.) I had previously tried many days of Kroil, PB Blaster, Freeze off, pipe wrenches, bench vises etc.
jmeb is offline  
Old 04-25-16, 01:13 PM
  #16  
clubman 
Youngman Grand
 
clubman's Avatar
 
Join Date: Jan 2010
Location: Nova Scotia
Posts: 7,234

Bikes: roadsters, club bikes, fixed and classic

Mentioned: 103 Post(s)
Tagged: 0 Thread(s)
Quoted: 1681 Post(s)
Liked 807 Times in 535 Posts
Apart from the various scientific applications of lube/hot/cold etc, I'd tighten the saddle (hard), flip bike upside down, plant my feet on saddle to hold it down, bend at the knees and reef away. I have a strong back to compensate for my slightly undersized brain.
clubman is offline  
Old 04-25-16, 01:39 PM
  #17  
jefnvk
Senior Member
 
jefnvk's Avatar
 
Join Date: Apr 2015
Location: Metro Detroit/AA
Posts: 8,212

Bikes: 2016 Novara Mazama

Mentioned: 63 Post(s)
Tagged: 0 Thread(s)
Quoted: 3634 Post(s)
Liked 73 Times in 43 Posts
Originally Posted by jmeb View Post
If you don't mind sacrificing the seatpost.... hack off the top of the SP with a hacksaw leaving a few inches exposed. Hacksaw down the length of the SP (i.e. inside the downtube). You'll know when you're through the soft aluminum post vs. the steel tube very quickly. Grab edge of cut with pliers, twist in and pull out.

This was the method that worked for me in a similar situation (rotation but no pulling out.) I had previously tried many days of Kroil, PB Blaster, Freeze off, pipe wrenches, bench vises etc.
What sort of hacksaw can you get in a seatpost? Is this something really long that you stick the blade down the seatpost, and reconnect in the bottom bracket?
jefnvk is offline  
Old 04-25-16, 01:51 PM
  #18  
Metacortex
Senior Member
 
Join Date: Apr 2011
Posts: 2,371

Bikes: Fillet-brazed Schwinns

Mentioned: 57 Post(s)
Tagged: 0 Thread(s)
Quoted: 208 Post(s)
Liked 14 Times in 11 Posts
Originally Posted by jefnvk View Post
What sort of hacksaw can you get in a seatpost?
One like this: https://www.bikeforums.net/bicycle-me...posts-out.html
Metacortex is offline  
Old 04-25-16, 01:56 PM
  #19  
squirtdad
Senior Member
 
squirtdad's Avatar
 
Join Date: Jul 2006
Location: San Jose (Willow Glen) Ca
Posts: 7,434

Bikes: 85 team Miyata (modern 5800 105) , '84 Team Miyata,(dura ace old school) '82 nishiski,

Mentioned: 72 Post(s)
Tagged: 0 Thread(s)
Quoted: 1316 Post(s)
Liked 575 Times in 412 Posts
Originally Posted by lostarchitect View Post
I'd try Freeze-Off before going to more drastic mechanical methods. This has worked for me in similar situations.
+1 on freeze off
__________________
Life is too short not to ride the best bike you have, as much as you can
squirtdad is offline  
Old 04-25-16, 01:58 PM
  #20  
jmeb
Senior Member
 
Join Date: Jul 2011
Location: Denver, CO
Posts: 676

Bikes: 1966 Carlton, 197X MKM, 1983 Trek 620, 1988 Schwinn High Sierra, 1995 DBR Axis Ti, 1999 Waterford, 2016 DBR Release, 2017 Surly Travelers Check

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Likes: 0
Liked 4 Times in 4 Posts
Originally Posted by jefnvk View Post
What sort of hacksaw can you get in a seatpost? Is this something really long that you stick the blade down the seatpost, and reconnect in the bottom bracket?
Originally Posted by Metacortex View Post
Something like that. I picked up just a basic handle at local hardware store that I could attach a hacksaw blade to. Sort of like a jab saw but with a longer blade on it.
jmeb is offline  
Old 04-25-16, 02:04 PM
  #21  
jefnvk
Senior Member
 
jefnvk's Avatar
 
Join Date: Apr 2015
Location: Metro Detroit/AA
Posts: 8,212

Bikes: 2016 Novara Mazama

Mentioned: 63 Post(s)
Tagged: 0 Thread(s)
Quoted: 3634 Post(s)
Liked 73 Times in 43 Posts
Originally Posted by Metacortex View Post
Creativity at its finest, I love it!
jefnvk is offline  
Old 04-25-16, 02:07 PM
  #22  
cyclotoine
Senior Member
 
cyclotoine's Avatar
 
Join Date: Jul 2004
Location: Yukon, Canada
Posts: 8,772
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 108 Post(s)
Likes: 0
Liked 8 Times in 8 Posts
also wrap an icepack around the frame while you twist and pull, or wait till winter and do it outside like I have done at -30 C

Or you could make the seatpost puller as discussed in another thread last week.
__________________
1 Super Record bike, 1 Nuovo Record bike, 1 Pista, 1 Road, 1 Cyclocross/Allrounder, 1 MTB, 1 Touring, 1 Fixed gear
cyclotoine is offline  
Old 04-25-16, 02:08 PM
  #23  
echo victor 
bicyclatte!
 
echo victor's Avatar
 
Join Date: Jun 2011
Location: San Diego, CA
Posts: 545
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 45 Post(s)
Likes: 0
Liked 1 Time in 1 Post
In addition to the other suggestions, I might try cooling the seatpost with dry ice or similar (carefully). The aluminum seatpost should contract more than the steel tube, and it should address the friction heat build up that you felt before.
__________________
If someone can pour a Guinness with a cycle instead of a shamrock on top, I'll update my profile pic.
echo victor is offline  
Old 04-25-16, 02:15 PM
  #24  
rgver
Senior Member
 
rgver's Avatar
 
Join Date: Jun 2012
Location: York, England after 15 years in Massachusetts
Posts: 608

Bikes: 1 frame and a heap of pieces

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
The post on my Motobecane was turning but not coming out, I got the post out with an air hammer, not gentle, not going to save the post and definitely not quiet but it worked pretty fast
rgver is offline  
Old 04-25-16, 02:33 PM
  #25  
corrado33
Senior Member
 
Join Date: Jun 2013
Location: Bozeman
Posts: 4,094

Bikes: 199? Landshark Roadshark, 198? Mondonico Diamond, 1987 Panasonic DX-5000, 1987 Bianchi Limited, Univega... Chrome..., 1989 Schwinn Woodlands, Motobecane USA Record, Raleigh Tokul 2

Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 1129 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by cyclotoine View Post
also wrap an icepack around the frame while you twist and pull, or wait till winter and do it outside like I have done at -30 C

Or you could make the seatpost puller as discussed in another thread last week.
You've got it the wrong way around. Shrink the seatpost (cold) expand the seat tube (heat.)
corrado33 is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.