Stuck seat post

I removed a stuck alu seatpost from a steel frame like that - soaked for a few days in WD40, then lots of boiling water and some stiff pulling. PlusGas would be better though if you can get some. Screwfix etc usually have it.

After that you are into building a rig to apply load at to the post back down to the bb. Your LBS might have similar already?

If properly stuck, then the only non-destructive method is to pull it out with some kind of tool e.g. seatpost man at Chorley or the various tools shown in YouTube videos. It can take 1-2 tonnes of force. 

I made a clamp block just a couple of weeks ago to remove my stuck dropper before Jennride. Luckily we have a 10 tonne crane and strong floor grid at work so pulled it one lunchtime.....

Thanks. Seat Post Man is my other option. But as this is going to be my lad's "Rat Bike" it may be cheaper just to source another frame.

If it were aluminium post in steel I have had some success on a stuck stem using plumbing pipe freezer spray filling the upturned steerer / fork to shrink the stem using differential expansion. You only have a very short period to smack it out whilst cold and significant risk of freeze burns.....

Posted by: Harry_the_Spider

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any other suggestions?

Squirt some of your chosen anti sieze solution into the seat tube via the bottle boss mounts when the frame is upside down? 

I many years ago when I didn't have a vice used a grid (at the edge of a road) to place the top of the seatpost in whilst using the whole frame as the lever to break the corrosion bond. Doesn't a always work tho as the top of the seatpost can break the glued bond from the post itself. 

Many moons ago a mate had good luck with WD40 and boiling water to remove a stuck post on a 4130 steel BMX. He also drilled a hole through the post used a massive screwdriver to twist it out whilst standing on the chainstays.

Yeah, I clamped a bar into the seat-clamp the opposite orientation to the saddle clamps to give me something to pull on and twist. It did damage the seatpost to the point of being unusable after, but the frame was fine. Drilling a hole for a screwdriver sounds better. Either way the post is getting binned unless you go the rig set up or have access to the sort of stuff mick_r has.

I've never had success with either chemicals (wd40 and a specific release spray) or combinations of heat and freezing.  What has worked for me was to embed a brand new hacksaw blade into a piece of thick dowel so only the teeth of the blade were exposed and only to the thickness of the seatpost.  I then used that to saw a notch in the seatpost and when I then twisted it it would start to separate from the bike frame and I sprayed more release chemical in there and kept twisting.  That worked perfectly but the seatpost was aluminium which is easier and I did it over several days so I would stop whenever I got tired and was no liner taking care.  Fwiw I used a saw blade with I high tooth count as that cuts aluminium better than steel but if your post is steel that bit won't help you 

I would probably try drilling a hole through the seatpost to either put a lever through as above first or putting a bolt through to give a vice better grip.  In any case the seatpost is toast

Before doing anything destructive to remove the post it's worth checking if it's at an OK height to start with.

And if you can't get enough grip on it to twist or pull, maybe smack it down with a lump hammer to break the corrosion seal.

Plus Gas or other penetrating oil is vastly superior to WD40 (which as the initials show is a Water Dispersant) and particularly effective on steel/steel stickages.

Hot and cold repeated worked for me.

Boiling water and then cold water 

A patient job. 

Hot water on frame and cold water as best as possible just to seatpost and then try and free it up.  Repeat and repeat....

I have been successful numerous times including a bargain frame sold with a stuck seatpost.

Good luck

If it's going to be a rat-bike can you use a blow-torch to warm things up a bit. 

Then rattle-can the burnt bits of the frame after if successful.

Finish line chill zone 

Do you not know some blokes who can do it at work in exchange for for a crate of Guinness??

Posted by: MrSparkle

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Do you not know some blokes who can do it at work in exchange for for a crate of Guinness??

Sadly I don't work there anymore!

I had an alu dropper stuck in a steel frame and tried absolutely everything at a normal persons disposal, including caustic soda or acid, whatever it is called. After much time and money spent on various chemicals and sprays, I sent it to Chorley. Should have just done that in the first place as the castic stuff messed my paintwork. This was a 1k frame so wasn't going anywhere. Service from Bikepost Man was perfect.

If there's any holes near the BB, turn bike upside down and get some just opened, warm cola down the seat tube for ~24hrs+, then spin right way up and with loosened post clamp tap the top of the saddle/post with a mallet hitting some wood instead of the bike bit.

I freed up an alloy post inside my 531 framed Peugeot road bike using this method ~30 years ago.

Caustic soda if it’s a beater. It’s so easy and you get clean pipes when you pour it down your drain after 😂

Just seen it is steel on steel. Didn’t know anyone still used a steel seat post. So ignore that 

Anywhere near Sheffield - happy to do it 

The two methods I've used:

Seat in a vice bike upside down 

Spray every day and ride around without a seat bolt.

Garages have to deal with steel-on-steel corrosion all the time.

I reckon an independent garage would have a go at it... they wouldn't want to be beaten by a bicycle LOL.

I have used Plus Gas with a good success rate for a variety of seized steel things.

I only ended up with the plus gas because the car mechanic left a tin in the boot of my car.

Lots better than wd40.