UKC

Having had success twice before using a Stilson wrench and a roof rack bar to remove stuck seat posts, I thought I'd use that method again, but all I succeeded in doing was turning the seat post head within the seat post.

Idea number two was to hammer two flat sides into the side of the seatpost so the wrench would have something to grip onto, which resulted in me in breaking the top part off the seat post.

I'm thinking idea number 3 needs a bit more finesse, might a Dremel long reach bit fit inside a seat post, and has anybody any thoughts on what kind of bit would most gradually wear away the inside of the seat post?

I had a thought that a wire brush kind of attachment could be good for getting through the aluminium seat post without harming the steel frame.

( It seems the lesson to take from this is the wrench and roof rack bar method is only safe for sturdy alu posts which are forged in one whole piece, as it's worked brilliantly in the past on cheap posts I've not minded harming when removing them in taking chunks out the metal. )

Does anybody have a long reach attachment they could measure the width of for me?

Many thanks.

Tim

In reply to Timmd:

You can use a hacksaw blade to cut a slot down the inside of the post before squashing is to release the post from the inside of the seat tube.

In reply to gethin_allen:
I've heard of that method, but I think I'm after a method that's incrementally easy to control, I've probably more faith in myself to not balls up using an extended Dremel with a wire brush end I think.

In reply to Timmd:

Drill right through the post and push a length of steel rod / screwdriver through to create a "T bar". Apply gentle heat and twist.

In reply to Timmd:

Use a plumbers freezing spray on the seat post and then a thump.

In reply to Timmd:
Liquid nitrogen worked for me so the plumbers spray sounds like a good idea.

In reply to Hafren:

Yep, and if that doesn't work, rig up some kind of slide hammer from a length of studding etc.
One tip I was recently told about for releasing seized exhaust studs was to heat, and then touch with a candle so that capiliary action draws the wax into the joint. I have absolutely no idea if this works or not, but it's a good opportunity for you to test the theory and report back

In reply to Timmd:

I can confirm that my flexi extension for dremel does fit inside a 31.6mm seatpost perfectly well with few mm to spare.

No idea what cutter would be best that wouldn't cut steel though - brush would probably work but take forever. you are also at risk of leaving some behind.

Can you drill into the post? a 10mm hole at 90 degrees to the post and a 9mm bit of steel bar (with a big lever extension) after being soaked in wd40 or similar overnight should allow you to get a good twisting force to get it moving. poor boiling water over the outside of the seattube at the same time (be quick tho as aluminium expands quicker than steel, so you don't want the heat to soak through before you start it moving.

next time use assembly paste!

In reply to balmybaldwin:
That's interesting to know, could you measure the width of your Dremel extender whatsit for me when you get a moment?

The stuck seatnpost is a 26.8mm diameter one.

I've seen on google about abrasive wire wool bits for Dremels, and I'm happy enough with it taking forever.

From having fiddled about with car doors and other steel things, I've a feeling that the wire brush bit will just leave the insides of my seat tube very shiny, and it's simple enough to use a torch to inspect the inside of the seat tube to check it's all been removed.

Since I found it was stuck I've used grease on all other alu posts in steel frame. It can sometimes only take 3 months or so it seems, if you're unlucky.

Thanks

In reply to Timmd:

It's going to take you about 6 weeks and god knows how many wire wool bits to get through an ally seatpost with a Dremel?

In reply to Removed User:
I didn't say wire wool.

There's a range of abrasive bits which would fit a Dremel.

https://www.google.co.uk/?gws_rd=ssl#q=dremel+abrasive+brush

Though seeing how you can get Bosch drill extensions, that's looking like a speedier way forward than a Dremel if I go down that route.

Or an abrasive flap wheel which would fit a Dremel. The frame is a junky one bought as a bike for £80 ten years ago as a shopping bike. It's as much about the process of working out how as saving the frame.

http://uk.farnell.com/flap-wheels

In reply to Timmd:

No, it won't fit inside a 26.8 seatpost. The clearance is too small on a 31.6.

In reply to Timmd:

If you've not tried already, squirt some Plus Gas on it. It makes WD40 look like treacle. Then I'd probably drill a hole and make a T-bar as suggested above to lever it round.

In reply to Timmd:

The wire brush in a a Dremmel wont touch it. A small round rotary burr would but I don't think you'll be able to get it in contact with what you want to remove and it would be very hard to control.

Personally I'd go for penetrating fluid and drill to fit T-bar option first, slide hammer second then when that's failed cut it out with a hacksaw blade, it'll go very slowly anyway and you can use insulation tape around the blade tip to guarantee you can't cut into the frame. Once you're most of the way through remove all but he last wrap or two of tape, finish the cut down to tape thickness and collapse it inward at the cut with a punch.

jk

In reply to jkarran:

Penetrating oil (which you've probably already tried), and then try hitting it further *into* the frame. It's the easiest loading to apply (hammer from above) and will likely break the corrosion products that are causing it to be stuck. Similar to slightly tightening seized bolts before trying to undo them.

I'd try that, probably in conjunction with a T-bar style approach if it didn't work on it's own initially.

In reply to Timmd:

Watching with interest as I have the same problem. Tried plus gas to no avail. Looking at ammonia next and then maybe caustic soda - yikes. You read Sheldon Browns tips?

In reply to iksander:
I've just bought a drill extender whatsit for the family Bosch drill and three abrasive flap bits which can be used for de-burring and removing rust and things, to use to wear away the seat post from within. I decided to go with my instincts as it were and use a method which feels right for me.

I'll let you know if it's worked once they arrive in the post.

In reply to Timmd:

How will you know when you've worn through the seat post? I think this idea might take a very very long time! Happy to be proven wrong though.

In reply to Timmd:

Heat the frame using a heat gun and not an open flame. Give the post a few taps with a hammer to break up the corrosion and twist with a Stilson wrench if there is any post sticking out of the frame.
Also add some penetrating oil, do this whilst it is still warm and the gaps will be bigger to allow better penetrating.
If you are round the Leeds area I would be willing to try extracting it using a set of internal bearing pullers that I have.