I have been away on holiday and on return I have found my seatpost is seized solid 😥 it was moving fine about 2 weeks ago! I filled the seat tube with vinegar and have left it for 3 days and tried to move it tonight using an old saddle and a big hammer but no joy so any tips are very welcome! Its a thomson post into a steel 456 frame. cheers

I forgot to add that its just had a nice new paint job so don’t really want to ruin the paint.

Try boiling water on the frame then repeat your efforts.

Bottom bracket out, caustic soda down the seat tube. You’ll need a new post afterwards, though.

Have you tried the seatpost in a vice and used the frame as leverage? This will also result in a scrap seatpost, unfortunately…

HTH.

Plus Gas. Proper penetrating lubricant. And hot water.

brant – Member

Plus Gas. Proper penetrating lubricant. And hot water.

+1

If this fails then make a funnel out of modelling clay around the joint between the fame and seat post fill with Plus-Gas, leave to soak for a few days, then boiling water on the frame and tap and twist the seat-post.

If this fail then you will probably have to resort to brute force.

Cheers all, where can I buy this Plus Gas from? Will I need a car place or a DIY shop? Luckily its set to the right height for 99% of my riding!

Sheldon Brown’s word on the topic here.

Any good hardware/diy shop should have some else a motor-factors or motorbike shop

If all else fails try the internet

Had the same with a Cotic and Thomson post…a week of Plus Gas + a couple of goes with hot water did the trick. Used an old pair of bars as leverage iirc

It’s out!!!! Hurrah : ) put wd40 in last night using the bluetak funnel trick and then used boiling water on frame and used a great big clamp from work with a long metal bar and got the strongest bloke to push it while the rest of us held the bike!! Well chuffed. Thanks everyone for your tips.

OP – now make sure that you put grease or antisieze on it so that it stays unstuck!

This.

Try this if anyone has same problem,heat frame by gas or hot water e.t.c then quickly cool inside seat post to contract the post,plumbers freezing gas should do the trick.