seized seatpost

dmch2

My alloy seatpost is seized in my alloy frame, it's FAR too low so I'd like to move it. I've looked on sheldon brown (http://www.sheldonbrown.com/stuck-seatposts.html) and the only options left are using a vice (which scares me in case I bend the frame) or a hacksaw (which scares me even more!).

gently levering the collar apart, heat, force, WD40 and ammonia have all failed so far.

It's not been hammered in or anything but it has been there for about 5 years and been rained on in the past.

Does anyone have any other tips?

Supergoose

It has to be the vice. Soak the pin from underneath via bottom bracket with WD40 or similar over a 24hr period. Accept that the post is for the bin, pop it in the vice, nip it tight. Then *tech term* shoogle it (the frame) like mad it comes out.

Perseverance is key.

Use copper grease on your new pin.

Best of British luck to you.

dmch2

So i need to buy a vice (i've got a nice big solid work table to bolt it too) first

Then seat off, mount the bike upside in the vice and spray half a can of wd40 through the hole which the cable guide screws into. That will then run round the (hollow) BB and down to the seat. ie I can leave the BB etc in place I think?

Then leave til the next day.

Do I just wiggle the frame side to side, back and forth, rotate and back etc with gradually more force until it goes? How hard can i lean on a hybrid frame before it'll get damaged?

Thanks for the good luck wishes!

Supergoose

Your bench is crying out for a vice. I would remove the bb and get as much loosening agent as possible down there. Dont be shy when it comes to rocking the frame, but if your WD does its job you wont need to swing on it too much.

Robert456

if the vice don't work, don't be afraid of the hacksaw approach, it does work and is not brutal as far as the frame is concerned (just be carful and cut nice and squarley). If your going to soak the frame upside down, why not fill it full of ammonia, although Sheldon suggests this for alloy to steel interferance, don't know if it's any good for alloy to alloy

dmch2

Ammonia apparently dissolves aluminum oxide which will be what is sticking the alloy of the frame to the alloy of the seatpost. I'll poor that down one day then if i doesn't work I can use WD40 the next.

I guess taking the BB out isn't really that much effort. Especially as it's only been in a couple of months.

I'd imagine that if I slip then headbutting the pedals would really hurt so that must be anothing thing in favour of taking out the BB!

If I need to junk the seatpost anyway then hacksawing it isn't going to cost any extra. Although trying the shoogle is a good excuse to buy a decent vice

Nigel Bennett

Yes, get a vice. Are you a cyclist or what? I cannot imagine what it must be like trying to fettle anything without having the ability to secure it to the planet at some point to batter it or otherwise attack it with manly appliances!

And if you've got the bench, you're most of the way there - a lot of folk without one simply have nowhere to put a vice.

Look at car boot sales - don't go and buy a new one; second-hand ones (unless really goosed) are just as good.

dmch2

Lack of vice is bad enough for a bike but even worse for fettling a car!

I hadn't though of using the vice a clamp to hold the bike in place when working on it. I was thinking of this one: http://www.machinemart.co.uk/shop/product/details/cvr4rb

It's cast iron, got a swivel base and 100mm opening width. More than ample for unseizing the saddle I hope.

It should easily take a tube with a block of wood each side to protect it. I guess making some bits of wood shaped to fit round the tube would be a good to stop things slipping.

Robert456

Whats the postage on that vice? Partco usually have big vices in stock if you have one near you

dmch2

No idea what the postage is - i'll go collect it as machine mart isn't far from my local evans where i'm going to choose a new road bike later this week

That means I can attack the hybrid's seized saddle and not worry if it's out of action for a while.

Andrew N

Local mechanic used a blow torch to free up and lever out my mate's seat post...gave a funky new colour scheme to the frame as well as releasing the seat post!

dmch2

I've tried heat (the wife's best hair dryer gets pretty hot) but not blow torch amounts of heat. To be honest I'd be scared to get it much hotter as I'd start stripping the paint.

edjo

firstly, go to Halfords or the like and get some Penetrating Fluid / Spray. this is designed to penetrate corroded parts and not just displace water like WD40.
spray onto seat post and the 'waggle this around to allow the fluid to penetrate the gap. do this a few more times and you may be lucky and it come free.
if not, spray on some more, waggle into the frame / post gap and then using a soft face hammer, tap the seat tube to encourage the fluid down. leave this overnight and then smack the top of the seatpost hard once with a hammer and try to extract.
if this doesn't work, then it's a vice. still use penetrating fluid though as it's much better than WD.

dmch2

I've tried both penetrating fluid and ammonia (which should dissolve aluminium oxide according to Sheldon Brown) followed by lots of wiggling along with hitting it. I'm used to unseizing car parts so I thought a bike would be easier!

edjo

take the saddle out and clamp two large screwdrivers in. use these for leverage and try to twist the post loose - goodbye seatpost with this! if this doesn't work, then it's almost certainly the vice. essentially, you've got two pieces of aluminium 'welded' together and breaking that weld can take some doing!

Mister W

Penetrating fluid won't work. If you've read Sheldon's comments on the properties of aluminium oxide you'll understand why. Ammonia is supposed to work but I've yet to find anyone who has had success with it (waits for the stampede of people who have been successful )

dmch2

Not sure i want to trash my screwdrivers - so it's the vice! New bike will be here in a week so then there's no excuse.

The ammonia i got (from homebase) is fairly dilute so maybe that's part of the problem. i'll leave the bike upside down and full of ammonia for a day before giving it a wiggle, pull twist etc. Then leave another day and pull a bit harder etc...

A mad rush of successful ammonia users would be good to here from though!

edjo

Mister W...not going to get into a disagreement with Sheldon as - unforunately - he's no longer with us. however, as aluminium oxide is extremely inert and not susceptible to reaction with weak ammonia solutions generally available, we're seeing a mechanical action rather than a chemical or electrochemical when ammonia solutions are used and a stuck post is released. penetrating fluids don't evaporate to nothing unlike WD40 and so allow some lubrication of the post aiding removal once the physical joint is broken; you do, however, have to get it in so some gaps are needed. Plus Gas is used in the aluminium forging industry for releasing and is extremely effective - it does have to be heated once in place to work at it's best.

Robert456

You may well find that the vice method snaps the top off your seatpost, better to clamp further down away from the seat mount

elcani

I successfully used ammonia (bought online, don't know how potent it was, it certainly stank) injected - over many many days -into the flutes of fluted aluminium seatpost stuck in a steel frame. I then found a mate with vice, clamped it and twisted it out. What I don't know is how much effect the ammonia treatment had.

Good luck and let us know what happens.

Buckled_Rims

Yeah, been there; done that...and ruined a frame!

The only method for a truly stuck post is to ream it out. The post only needs to be reamed to half its thickness before it starts to collapse....so says someone on another forum post.

dmch2

A mate has a huge vice spare and no space for a bench so he's said I can have it. I'll get it bolted in place and attack the bike once the new Trek arrives.

If it won't twist out then I'm hopeful that we'll stop before the point of doing any damage to the frame so we can then hacksaw it off and then split it by sawing lengthways.

Although I shouldn't worry as I'll be too happy on the new bike (until the salt arrives)

To ream it out I guess you'd need a pillar drill with a 30mm (or whatever) drill? Not sure I've got one of them...

crankycrank

dmch2 wrote:

To ream it out I guess you'd need a pillar drill with a 30mm (or whatever) drill? Not sure I've got one of them...

Nope, all you need is a wrench to turn the square head of the reamer or you could clamp it in the vise which is what many shops do when reaming seat tubes.

dmch2

That sounds a lot more fun than hacksawing it out.

http://www.totoolsupplies.co.uk/uk2ecommerce/product/toolex_straight_shank_reamer_29_01_-_29_99mm/ looks to be the job but £100 is a bit steep. Is it just a case of 'that's what it costs' or do you know of a cheaper supply?

Any excuse to buy new tools

crankycrank

dmch2 wrote:

Is it just a case of 'that's what it costs' or do you know of a cheaper supply? Any excuse to buy new tools

I'm in the US so don't know where to buy in the UK but you should be able to find a cheap, adjustable hand reamer for around 25 quid or less.

simon johnson

I had this problem:

Left some oil to soak...heated up area with a hairdryer...placed an old saddle on there, then using a long, dense piece of wood (running it through the saddle rails) I was able to wind it free using the length of wood as a lever. I guess a strong tube of metal would do better. The saddle was a wreck sfterwards though.

Robert456

It your going to use the vice and twist method, keep an eye on the paint around the seat, top and rear stay junctions, any cracking and you know that you are severly flexing the frame. It might be that the vice gives you that bit more leverage that you need, anything approaching brute force I would abandon and consider the hacksaw a saffer bet. Once you have cut your slot, you simply put the post into the voce and crush the seatpost which will free it with ease and it should then simply lift out.

dmch2

Inspired by simon's 'long piece of wood' idea I tried a big adjustable spanner on the block that the saddle mounts onto. Then put a 3 ft long metal bar on the end.

That just started moving the 'block' in the seatpost rather than the seatpost in the frame.

crankycrank - can you really get enough force by hand to ream it out? Or do you just shave a tiny tiny layer off each turn and keep being patient?

crankycrank

dmch2 wrote:

crankycrank - can you really get enough force by hand to ream it out? Or do you just shave a tiny tiny layer off each turn and keep being patient?

Usually you end up taking a tiny layer at a time although you might get lucky and have the post break loose at some point before completely taking it down to nothing. Alu usually cuts pretty fast and not nearly as much strength is needed as for reaming steel . Prepare for a fair amount of work and hope for the best. I would make one more suggestion before buying any tools though. Pour some ice cold water into the seatpost into your upside down frame. Let it sit for 30min or so preferably replacing the cold water every 10mins. Then pour out the water and pour boiling water over the seatube around where the post is and try to twist the post. If this doesn't work after a couple of tries then ream away.

norfolkandgood

If you have enough seat post sticking out and know a plumber then there is a tool I use at work which freezes pipes. It will freeze the post down to about -20 deg C and may help if this is combined with a quick hair dryer on the outside of the seat tube. You can buy a DIY version which works with a type of spray can, a little like spraying a Co2 fire extinguisher if you know what I mean. The version I use takes 20 minutes to freeze a 22mm pipe full of water. Costs several hundred pounds though.

dmch2

Ha ha! I won!

A very big vice donated by my mate clamped tight enough to bite into the seat tube with the bike upside down and my weight leaning hard at the forks end of the frame. A very big creak and it moved a fraction.

Then more pushing, pulling, twisting, rocking and it gradually eased out.

I guess i need some steel wool on a stick to clean the inside of the frame then any cheapish new *greased* alloy seatpost?

Thanks for all the suggestions