Author Topic: Removing a stuck seatpin (steel frame)  (Read 9925 times)

Removing a stuck seatpin (steel frame)
« on: July 04, 2011, 02:30:37 pm »
Hi
The frame is steel (nice 653 frame I'm sorting out after not riding for a while and don't want to bin), and I assume the seatpost is aluminium alloy of some sort.
I'm aware of the previous thread on this and this advice: 15 Ways to Unstick a Seatpost

I tried the freezing method yesterday (boiling water on the seat tube and a plumbers pipe freezer thing on the seatpost. All I achieved was this:

Pug seatpin 3 by duncancmartin, on Flickr

The LBS suggested I could drill the seatpost and put a bolt in it and then put it in a big vise, but this could kill the frame. Their alternate suggestion was find someone to melt the post out (it's lugged, so the melting point of the brazing material might be an issue)!  :o They felt this was less likey to damage the frame than the hacksaw down the tube method.

An alternative that just occurred to me is to put a cork in the seat post and fill the whole tube with a rust eater like Jenolite (throught the bottle bosses ideally).

I'm slightly confused now.  What do you think is the best option (or at least the one least likely to wreck the frame? Or am I best off sending it to a framebuilder and making it someone elses problem? The forks are chromed and quite pitted, so if it's getting sent off it would be a good idea to sort them as well I guess.

I was hoping to avoid spending too much recommissioning this so I could also build a retro MTB!

Any help/opinions gratefully recieved!
Cheers
Duncan

LEE

Re: Removing a stuck seatpin (steel frame)
« Reply #1 on: July 04, 2011, 02:32:38 pm »
See Here (a sort of last resort)

http://yacf.co.uk/forum/index.php?topic=36893.0

LittleWheelsandBig

  • Whimsy Rider
Re: Removing a stuck seatpin (steel frame)
« Reply #2 on: July 04, 2011, 02:35:05 pm »
The melting point of aluminium is very low.  Even a silver-soldered frame would be fine, as long as you don't go overboard with the heat.  The paint will be dead though.

It is bloody hard/slow work to hacksaw out a seat post and even harder to do so without marking the seat tube.
Wheel meet again, don't know where, don't know when...

Re: Removing a stuck seatpin (steel frame)
« Reply #3 on: July 04, 2011, 02:38:53 pm »
Have an Overburys 700c, bought for riding in Rome and environs when GF was still living there. Bought second hand spa sputnik wheels  for it (Rome is very cobbled at the centre and the Via Appia isnt kind on wheels). While sorting the bike out, biggest issue was the seatpost. Stuck, stuck and stuck. Tried almost everything in that thread. No luck. Really liked the frame, very comfy and all that.

So, took it to Argos. Sorted. Wish I had done that sooner. Argos will touch up your frame afterwards with approximate matching colours.

Frere




Re: Removing a stuck seatpin (steel frame)
« Reply #4 on: July 04, 2011, 04:47:54 pm »
Thanks for the info on caustic soda. I don't fancy that method as I have a 2 year old running around the back garden, and there's not enough space in the garage (full of immobile knackered classic car). Sounds like fun though. :)

The bike shop my LBS said might melt the tube out have said they will have a go. I'll take it over there on Saturday (if I can't get it there sooner). I'll update this thread when they've had a look...

Cheers
Duncan

PS Here's the bike :):

Pug seatpin 2 by duncancmartin, on Flickr

Re: Removing a stuck seatpin (steel frame)
« Reply #5 on: July 04, 2011, 11:25:13 pm »
I spent a summer (or it felt like it) removing 3 aluminium pins from 3 steel frames. I had been a bit lax about maintenace up to that point.

They all came out. I tried most things. I can't say that one thing did the trick on any of them. I used ammonia (toilet cleaner from Wilko, I think), leverage (hole through the seatpin, then a long steel bar as a lever) and, on the last one, the cutting method.

Cutting the pin isn't as difficult as it sounds, if you give yourself enough time.

Allow 30 mins (lucky) or 1-2 hours (unlucky). Take it easy.

Cut the pin off about 1.5" above the seat tube. Get a good hacksaw blade. Wrap one end with some padding.

Lucky:

Cut down the visible pin and into it below the tube line, at an angle so that you aren't cutting the steel tube. When you've cut some pin inside the tube, try crushing the available tube with big pliers or a G cramp. If you're lucky (see subheading) you'll free enough of the stuck pin to be able to move the rest. Keep using lublicant/wd40. If you get any movement at all, the oil/wd40 will get in there and help a little.

Unlucky

Ok, so cutting the pin down from the top hasn't worked. It didn't work for me either. I just hoped it might. Now you're in for the long haul.

Start sawing so that the end of the hacksaw blade in the tube is touching the tube. The end has no teeth on it, so won't damage the inside of the tube.

Slowly, very slowly, over a period of minutes, maybe hours, possibly days, bring the blade more in line with the tube (but never exactly in line, because then you will be cutting the tube). Even if you do not cut the pin to the tube - something to avoid - you will weaken the internal structure of the pin. The idea is to do so until it is weak enough to crush it. Be prepared: you may need to cut it twice (two parallel cuts down the inside of the pin).

Eventually though it will give way. You just have to be really careful and very patient.

When you have done it, you will feel many things. I'll be grateful if you can put those feelings into words.

Paul.

L'enfer, c'est les autos.

Re: Removing a stuck seatpin (steel frame)
« Reply #6 on: July 04, 2011, 11:34:29 pm »
For info only, not touting for business :o There are two options.
1) if the frame is being resprayed or you are not bothered about the paint. I heat the outside of the seat tube evenly over the area of the pin, gently and nowhere near the melting point of the braze or even silver solder. Difficult to describe as each one is different. Then walk away and let ot cool completely (at least 1/2 hour) For the next step you need a big vice on a solid bench. Grip the pin along the vice jaws to get the max contact area and get the vice as tight as poss. Then, using the frame as a levertry to get the pin moving. Usually it will shift fairly quickly then I add some Plus Gas or Contec Duck Oil through the clamp slot and keep working it until it comes out. This works best with two people, one pulling and one twisting.
The heat destroys the corrosion and the mechanical action disintegrates it.
2) I use a tungsten carbide burr on an extension shaft mounted in an industrial pneumatic die grinder to split the seat pin into two parts. However not everyone has one of these in the garage and it is a bit nerve wracking
The first method works well. I have shifted literally hundreds of stuck pins using this method.
Best advice is, if in doubt leave it to a pro !! I have lost count of the jobs that have been far more complicated and thus expensive because someone "had a go" and made a complete horlicks of it.

Cheers

Dave Yates
It's not just hitting it with a hammer but knowing where to hit it and how hard

Simonb

Re: Removing a stuck seatpin (steel frame)
« Reply #7 on: July 04, 2011, 11:43:55 pm »
From the man himself!

Re: Removing a stuck seatpin (steel frame)
« Reply #8 on: July 05, 2011, 07:22:46 am »


My fixed Dawes looks like that ( stuck seat post I mean ) - but mine is truly stuck.  So much so that I am not even worried about it anymore.  It was many hands old and too big for me anyway.  I will strip it when I get a new frame / fork and start again.  I can understand why you would not want to do that with a lovely frame like yours though.

Re: Removing a stuck seatpin (steel frame)
« Reply #9 on: July 06, 2011, 08:23:31 pm »
I took it to the bike shop today and they said they would try the alternatives before trying to melt it as that would damage the paint to halfway down on the seat tube, top tube and chain stay. I don't need the frame any time soon (I still need to build the new back wheel), so they can take their time.

Thanks for all the advice. If they say they have to wreck the paint and melt it out, I might send it off to Argos (or Mr Yates  :)). I bet they do this sort of thing more often than a LBS (and have more ability to sort the paint if it does need touching up).

I like working on the bike, and I'm happy to fettle/build wheels etc, but I don't want to wreck the frame by accident! Hence taking it to someone more qualified.  ;) It's been stuck for at least a year, but the bike needed a new wheel, mech, cables etc, so it got left alone. Now I want to sort everything and ride it, so the seatpost needs doing...

Cheers
Duncan

Re: Removing a stuck seatpin (steel frame)
« Reply #10 on: July 06, 2011, 11:02:43 pm »
My fave method would be the caustic, no chance of damaging the paintwork but try this as alternative.
Hire/ borrow a plumbers wrench known as a Stillson wrench . lay the frame flat and squirt some freeze spray into the seat post ,just enough for the post. Then using the stillson wrench twist the seat post, it'll help if someone can steady/ twist the frame while you're doing this. With luck the alloy will contract more and you might even save the pin. Good luck.

Re: Removing a stuck seatpin (steel frame)
« Reply #11 on: July 07, 2011, 07:14:43 pm »
The LBS called me and said they couldn't shift it mechanically and didn't want to melt it for fear of blowing a hole in the seat tube. 653 is too thin for them to risk it.

So I figure I should probably take/send it to a pro framebuilder. Irritatingly there don't seem to be any near Oxford. It would be nice to show someone the frame and forks and see what they say about whether it's worth refurbing them at the same time. The (chromed) forks are fairly pitted, bit the paint on the frame is actually pretty good. Anyone know who/where my nearest reputable framebuilder is? Are there any in west London?

Also, how much would a refurbed Pug be worth relative to how much it would cost? If the choice is spending a few hundred on the Peugeot f&f or buying a Colnago one, I think I'd be getting a new frame!
It would have to be steel though - 8 speed campag and my current finishing kit wouldn't look right on a newer style frame...

Decisions decisions...

Re: Removing a stuck seatpin (steel frame)
« Reply #12 on: July 07, 2011, 10:25:48 pm »
It's a no brainer! Go get the caustic. Remove bb, plug the small hole at the base of the seat tube. fill seat tube with caustic and water and leave for a few days.
The alloy seat post will have dissolved and paint intact. Then with the money you've saved you can buy the Colnago as well !

LEE

Re: Removing a stuck seatpin (steel frame)
« Reply #13 on: July 07, 2011, 11:55:18 pm »
It's a no brainer! Go get the caustic. Remove bb, plug the small hole at the base of the seat tube. fill seat tube with caustic and water and leave for a few days.
The alloy seat post will have dissolved and paint intact. Then with the money you've saved you can buy the Colnago as well !

Give it a go.  £5 (wear gloves and goggles).

It will be even less messy if you have a lot of seat tube showing.  I mistakenly sawed mine off a couple of inches above the seat tube.  because you have a lot of tube left, I reckon a day on Caustic would be enough to free it with a vice.  Mine took a week because I waited until it had completely dissolved.

Re: Removing a stuck seatpin (steel frame)
« Reply #14 on: July 08, 2011, 06:40:34 pm »
I'm coming round to the idea of caustic. If it doesn't work I can always send it off afterwards. I have a couple of questions though.

1. I assume the BB needs to come out. How about the headset?
2. If I make it too strong, will the heat created screw up my paint anyway (in which case I should have just sent it off)?
3. How much ventilation is needed? Can I get away with just leaving my garage door open?

Cheers
Duncan

Panoramix

  • 50 61 6E 6F 72 61 6D 69 78
  • Suus cuique crepitus bene olet
    • Some routes
Re: Removing a stuck seatpin (steel frame)
« Reply #15 on: July 08, 2011, 06:50:47 pm »
I once got one out by wrapping a carrier bag full of ice around the seat post and heating gently the frame with a hairdryer. After 5 minutes, I removed it with relatively little force (just using the saddle as lever arm and rotating it slowly)

Re: Removing a stuck seatpin (steel frame)
« Reply #16 on: July 08, 2011, 09:31:30 pm »
Just remove the BB, but make sure you plug the seat tube where it meets the BB. The head set will not be affected.
Fill seat tube with caustic granules and water and leave for several days . When I did it I checked it every couple of days and topped up with water and granules to within half an inch of the top of the seat tube as reqd. At the end of the week the post was totally dissolved,gave it a good wash out and everything was ok. There was no problem with fumes.

Re: Removing a stuck seatpin (steel frame)
« Reply #17 on: July 09, 2011, 09:52:43 pm »
So I got my caustic soda, and a friendly bike shop undid the BB so I could take it out when i got home.

I removed it, and discovered a wierd plastic/rubber thing inside the BB shell. Anyne know what this is or whether I need to save it?

Pug bottom bracket shell by duncancmartin, on Flickr

The bottom bracket is an old (but functional and still shiny) unit that looks like this:

Pug bottom bracket by duncancmartin, on Flickr

Is it OK for me to just rip out that liner, or would that mean I need a new BB. I've not done anything with BBs that aren't sealed before...

Cheers
Duncan

LittleWheelsandBig

  • Whimsy Rider
Re: Removing a stuck seatpin (steel frame)
« Reply #18 on: July 09, 2011, 10:05:37 pm »
That is a dust shield to stop crap getting into the bearings. Just pull it out and refit it if you reuse the BB.
Wheel meet again, don't know where, don't know when...

Re: Removing a stuck seatpin (steel frame)
« Reply #19 on: July 09, 2011, 10:21:58 pm »
If I destroy it, are new ones available?  Just trying to work out how much force to use.  ;)

Re: Removing a stuck seatpin (steel frame)
« Reply #20 on: July 09, 2011, 10:32:33 pm »
It's just a plastic sleeve - when fitted they usually concertina-ed a bit and if it has been in for years the plastic will have hardened off. It'll pull out easily enough, but it it rips this (I suspect) is a replacement:

http://www.spacycles.co.uk/products.php?plid=m2b0s110p1763

Re: Removing a stuck seatpin (steel frame)
« Reply #21 on: July 09, 2011, 11:43:08 pm »
A new Veloce BB is only 20 quid. Maybe it's a worthwhile upgrade anyway.
Getting ahead of myself - need to get the seatpost out first! :)
Cheers
Duncan

Re: Removing a stuck seatpin (steel frame)
« Reply #22 on: July 10, 2011, 05:06:57 pm »
The BB dust protector came out intact. :)

The seatpost is now happily hissing away. :) There is a drip coming from the bottom bracket area though and the level is going down. :( I guess my blue tac plug wasn't solid enough. I used amlost a whole pack of blue tac though!

I assume I should clean the paintwork and have another go later?
How much seatpost do you reckon I need to remove before I can pull it out? I'm guessing 4 days or so of sizzling?

Cheers
Duncan

Re: Removing a stuck seatpin (steel frame)
« Reply #23 on: July 10, 2011, 06:33:10 pm »
Still fizzing. I just checked and the level hadn't fallen very far, so maybe the blue tac is holding. :) I topped it up again, andit fizzed some more...

I'm away from home for a couple of days from tomorrow. I assume it's safe to leave it alone - it's hardly going to fizz over after being in there for a day is it? There's a bucket underneath it all should the blue tac break...

LEE

Re: Removing a stuck seatpin (steel frame)
« Reply #24 on: July 10, 2011, 08:38:43 pm »
Still fizzing. I just checked and the level hadn't fallen very far, so maybe the blue tac is holding. :) I topped it up again, andit fizzed some more...

I'm away from home for a couple of days from tomorrow. I assume it's safe to leave it alone - it's hardly going to fizz over after being in there for a day is it? There's a bucket underneath it all should the blue tac break...

After the initial fizz has died down (15 mins) it's usually calm down there.

At the strength I mixed it he fizzing was downright boiling out of the tube.  I needed to hose the seat tube down to save the paint.  It only lasted a few minutes though.  Should be safe to leave.

As for the blu-Tack, wrap a cable tie(s) through the BB and around the seat tube/down tube/BB joint to hold it in.

You need to leave it as long as it takes but mine was totally dissolved within a week, I'm sure it would have twisted out a few days before, I just didn't have enough seat-post to grab.