Bike seat post stuck - help!

[gidon]

Hi all

Has anyone got any ideas how to remove a seat post from a bike?

I've tried everything: the frame in a large vice, lots of WD40 etc etc. Now I've cut the tube off and cut a slot in the top of the tube but still no luck. I took it to a local bike shop some time bike and he couldn't do it. The aluminium seems to have welded to the frame!

I'm really stuck - the only idea I have is to drill the tube out but I woudn't be able to do that.

Thanks,

Gidon

 

[OLD]

Just to break the seal drive it in then stilsons to start it moving and extract with help from wd40.

 

[jasonB]

Use just a hacksaw blade and put 3 slots right through the hole of the seat post(alloy tube) then use a large pair of grips to compress the post, it should come away from the steel frame, you do need to cut the full length of the alloy thats inside the frame.

A smear of waterproof grease or copperslip will stop the new one corroding in

J

 

[gnu]

No don't start messing around with hack saws. Take it to a quality bike shop and they will remove it for you or go to Sheldon Browns website, CTC, bike forums or cyclechat. For godsake don't start messing about with grips or you could damage the frame.

 

[jasonB]

Well that was advice from my uncle who was a frame builder before retiring after 40plus years of making bikes if all else had failed, but he is aware that I know what I'm doing when it comes to metal working.

Jason

 

[mbartlett99]

You haven't said if the frame is steel or not, if its ally you've got a problem but if its steel then heat and chemicals can come to play.

If you can't slot it with a hacksaw blade (in at least two places to then relieve then pressure) knock out the small section between the cuts - carefully - the rest should come out pretty easily.

Remove the bottom bracket, invert frame, plug seatpost fill dowtube with chemical that eats ally - not caustic soda. For a gently approach try vinegar and leave it for a few days, otherwise a mild acid.

Please don't use Copaslip when you're done - copper and ally don't mix. A nice teflon lube like Tefgel will work forever.

Good luck, I know what a pain in the bum it is.

 

[gidon]

Thank you all for your help!

I have taken it to bike shop and they told me there was nothing they could do! Believe me I was happy to pay someone to do this.

Anyhow I've tried Jason's suggestion and am knackered. Still no luck. Then resorted to jig saw which worked ok as well but still no luck. I could knock out some sections - but only a couple of inches down. Then tried hammering it to get it moving and now I can safely say that the bikes a gonner! The acid idea may work - thanks - but I'm not comfortable taking bottom bracket off and prolly spent too much time on this now .

The bike is a 20 year old Saracen mountain bike - the frame is heavy - guess it's steel or some alloy. I think the problem is the seatpost is a good 6" into the frame otherwise I think Jason's suggestion would work.

I would never have believed this could be the death of the bike. Will apply grease in future!

Thanks again - not been here for a while and forgotten just how helpful you all are!

Cheers

Gidon

 

[jasonB]

You should still be able to saw the 6" down,thats why I said just use teh blade, a jiggy will butcher it. Have a break and do a bit more in the morning, only going part way and just bending the bits into the middle will just tighten things up. Hardest part is making sure you don't run the blade against the steel tube too much, if you do get it out have it reamed to clean up any burrs before fitting a new seatpost.

J

 

[studders]

Some Moons ago I had to cut one out with an oxy torch, no other method worked it was that corroded to the frame.

 

[Jacob]

Steel bikes are only brazed so a frame builder could probably take out the seat tube (including the post) and put in a new one, but probably not worth the bother.
I had same prob on my Dawes but got it loose in the end with alternating heat, wd40, gentle taps and turns, but not easy without damaging the frame.

PS just remembered another wangle - warm the frame and freeze the seat post with some spray gizmo which I've been told about but know little else. Plumbers kit? Flood with wd40 or meths at the same time.

 

[jasonB]

A saracen of that vintage would likely be tig welded in taiwan and the costs of cutting up the frame, rewelding and painting would not be worthwhile.

Jason

 

[matt]

Given the seatpost if probably the most disposable bit I'd apply some heat to that. Sure it will cause the post to expand in the first instance but, at the end of the day, any movement will be good for the cause.

If it's a steel frame then it will have some give in it. I'd clamp the seatpost in a good vice and then very very gently twist the frame back and forth a small amount, using the leverage of the frame and it's slight springiness to ease the post without actually bending the frame. Alternatively, drill a hole through the seatpost large enough to take a reasonable solid (and long) bar - then again, gently use the leverage back and forth.

Final idea... measure the seatpost hole and see if you can buy a smaller diameter post to inside

 

[Chems]

Thank you all for your help!

I have taken it to bike shop and they told me there was nothing they could do! Believe me I was happy to pay someone to do this.

Anyhow I've tried Jason's suggestion and am knackered. Still no luck. Then resorted to jig saw which worked ok as well but still no luck. I could knock out some sections - but only a couple of inches down. Then tried hammering it to get it moving and now I can safely say that the bikes a gonner! The acid idea may work - thanks - but I'm not comfortable taking bottom bracket off and prolly spent too much time on this now .

The bike is a 20 year old Saracen mountain bike - the frame is heavy - guess it's steel or some alloy. I think the problem is the seatpost is a good 6" into the frame otherwise I think Jason's suggestion would work.

I would never have believed this could be the death of the bike. Will apply grease in future!

Thanks again - not been here for a while and forgotten just how helpful you all are!

Cheers

Gidon

Take it to your local fire station and challenge the watch to see if they can remove it with their RTC gear. I'm sure they'd enjoy that as a bit of a drill.

 

[Noel]

Forget about chemicals and heat. Jason speaketh the truth.

Fine hacksaw blade (as you will get little purchase) and cut in 3 places on the inside of the post. As you cut bend the sections into the middle about every inch or so with a drift or steel bar or whatever is handy (nothing too sharp as you'll easily dent or puncture the down tube as you gently hammer). With a little help these one inch tabs will break off. It's hard work and easy to get 'effed off as you have found out. As you gradually get to the bottom of the post it will fall away. There will be plenty of swarf and bits of alloy falling on the BB if you forgot to stuff a cloth down the seat tube, an air line and a good shaking will get most of it out. Hopefully there is a protective sleeve on the BB but no big deal if not.
Once out get a large dowel or a floor brush shaft wrapped with abrasive and clean out the inside of the seat post. You may have to go down a mil or so in size with the new post or at least give the new post a good rubbing with abrasive as it'll be more than likely a tight fit which is what you don't really want..... I personally wouldn't use a lubricant/protection (just remember to adjust it now and then) but if you do, keep it away from the binder bolt or QR at the seat tube collar.
Don't give up whatever you do.

 

[bugbear]

The bible:

http://www.sheldonbrown.com/stuck-seatposts.html

From the late, great, Sheldon Brown.

BugBear

 

[Pvt_Ryan]

My uncle had a similar problem getting the down pipes off his motor bike, he got his son to go out everyday for a week morning and evening and spray on some WD40 and that freed the whole thing up.

Another thing you could try is concentrated Phospheric acid, it will eat the rust (converting it back to Iron) but leave the AL & steel alone, I would avoid other acids as they won't be as fussy about which metal they eat.

 

[jasonB]

I see Sheldon Browns last resort is what I suggested all along and I also said thsi was what to try if all else failed, My Uncle Tom knows his stuff (T.J. Quick cycles)

"If nothing else works, the final resort is the old hacksaw blade trick. Cut the seatpost off so that about 1/2" is left sticking out, then insert a hacksaw blade into the seatpost and carefully cut a slit in the post. This is very laborious, and you run the risk of damaging the frame if you cut too far, but this approach cannot fail. Once you have cut the slit, grab one edge of the cut with a locking plier and roll the seatpost up inside itself and pull it out. "

J

 

[matt]

T.J. Quick cycles

As in Stanstead Rd, South East London? He used to true my wheels for me when I was a kid (about 25-30 years ago) as I hovered in awe of the frames and bikes in his shop. Nice chap, always had time for me and my mates despite our cycles lack of pedigree compared to his normal fare.

Vaguely recall seeing T J Quick in Croydon more recently (or maybe it was another of cycle shops from my youth). Memory is failing me slight...

Small world.

 

[pablopete80]

The frame would be steel and depending on price could be handmade in the UK (kili *) or imported (* trax) which makes no difference as its now dead. Anyway the only successful method we used was lube, big vice and lots of controlled force. Various companies produce seat post reamers but these are for fine adjustment not mass removal. These would be used by good bikeshops with a well equipped workshop and may be used progressively to remove most of it or take it to a common size (25.4,26.8,27.2) and new post inside the old post. Other methods have been used but the time makes them very expensive in labour. So I think the point I am trying to make is if the vice did not work then most others won't either.

 

[jasonB]

Thats him Matt. Had his first shop in Dulwich just round the corner from Herne Hill track, then went to Batersea before Forest Hill. When He retired he sold it to the Goodes, members of the De laune CC who had it for less than 2 years before closing up. I had him make me a mountain bike to my own design, still got it in the shed but have not swung my leg over it for a few years, still involved with the De laune as my Dad who's been a member for over 50yrs and now Edits their monthly mag.

You are probably thinking of Roberts Cycles, just down the road from South London Hardwoods new shop.

Jason