I can't lower the seat - it seem to be stuck.

[Colin Trunt]

I have a bike its old about 10 years slight rust (1%?) on the stem which goes into frame. I can't shift it, any ideas?

I took off the saddle and gave it a wack or two with a hammer but no luck. I have taken he bold out and tried to lever it opwn at the 'join' but it don't seem to make much difference.

I was thinking heat but it will be hard to heat the frame with out damaging it.

I just had another idea - ice - maybe I can pack the part of the stem which sticks out with ice?

Hmm intersting, a fire and ice solution???

[Arfa Daily]

This seems like it might be a 'real' use for WD40 !! :-)

Arfa

[kimble]

[Nige Danton]

-- Nige Danton

[RubberBiker]

Useless. You're only causing a 20 degree temperature change at most - the differential contraction of the metal isn't significant.

[PeterC]

Yes; had it been an ally post it might have helped. My seat pins are always lightly greased and then removed, cleaned and regreased every 3 - 4 years.

[Rob G]

The cheapest and best 'penetrating' oil is paraffin, AKA CH oil. It is the thinnest oil of the lot and will penetrate far better correspondingly. Remember that WD40 was developed as a Water Dispersal agent for protecting missiles, not a freeing or lubrication material.

I would somehow arrange the post in a manner that it can be soaked for at least 24 hours in paraffin.

Rob

[Rob G]

And I then remembered that, in line with Sheldon's last recommendation, there is also the UKDIY's all-encompassing solution of the ANGLE GRINDER !!

[Gordon Henderson]

Stuff I've used in the past (not for set posts but for rusty nuts) is something called PlusGas. Not sure if you can get it now though - it's probably full of harmfull chemistry...

However - A quick google shows it's still being made!

Gordon

[Invisible Man]

Might have changed a bit since I remember it about 40 years ago.

[Tosspot]

The tyres take up a lot energy this way. In the past, when this seems like a solution, plenty of penetrating oil, leave overnight, put a wooden block under the BB, the hit it with a big fuckoff hammer.

Once it moves a millimeter *don't keep hitting it*, twist and pull. Oh, and in case you've not noticed, it's Dogs way of telling you to grease the post before reassembly :)

[Frank Erskine]

On Tue, 16 Jun 2009 08:57:51 +0100, Invisible Man had this to say:

,

It seems to be much the same as before - except that it's now in a naerosol can rather than a tin with a naluminium spout.

WD-40 is quite useless as a penetrating fluid.

[Dave Liquorice]

No still avaialble and the best penetrating/easing stuff about. Much better than paraffin, diesel or WD40. Of course if you havn't got any I'd go for paraffin then diesel. Most people can probably get a few drops of diesel easier than the other two, a few drops is all you need.

[Andy Dingley]

Still around, still far better than WD-40 or paraffin/kerosene

[Peter Parry]

Actually it is quite good. Some years ago DERA did a small evaluation of various penetrating fluids for a particular project and I used to have a copy of the report. WD40 outperformed most penetrating fluids (including Plus Gas). The test involved rusted nuts on bolts, rusted studs and rusted pins in holes (all steel). The most difficult aspect of the tests was achieving consistency in the rust. As far as I can remember some Astrolan liquid came top closely followed by WD40 and then a variety of others including diesel fuel. Paraffin alone was not recommended as if it was left it accelerated corrosion.

[David Damerell]

Quoting Colin Trunt :

Put the saddle back on. It's a lot easier to break such a lock by rotating the seatpost than by trying to hammer it up and down.

You might also try trickling lubricant or various break-loose potions into the seat tube, but I've never had one stuck so hard that a really good saddle twist wouldn't remove it.

[David Damerell]

Quoting RubberBiker :

You can do more with a heat gun (assuming the metals of frame and seatpost don't render this obviously futile). Heat it up until the paint blisters then stop two minutes ago. :-/

I've extracted stuck BBs with a combination of a heat gun, a 2 foot bar, and a 100kg housemate.

[Rob Morley]

Travel back in time 10 years and grease the seatpost.

That will do nothing to loosen it, and could damage the frame.

You may find that heating the seatpost helps - it's certainly easier than heating the frame, and less likely to cause damage. Just prop it on the gas cooker and leave it until the paint starts to look a bit worried. At this point I sometimes give it a good squirt of WD40/GT85/whatever else I have to hand, but I'm not sure if that does much apart from making smoke. Then clamp the seatpost up in a vice and give it a good twist. If you don't have a meaty vice then Stilsons are good too.

As others have already suggested, PlusGas is an excellent penetrating lubricant. Apply, leave to soak for a day, try to shift the stuck bit. Repeat as required. Stilsons are definitely the way to go here.

[Bob Mannix]

Wise words from someone without prejudice or pre-conceptions. I have found the same myself. The main problem with WD40 (and PlusGas) is that some are under the mistaken belief they are lubricants. Penetrating, easing and temporary squeak stoppers only.

[Arfa Daily]

It's amazing how many people think that WD40 is the very finest thing to squirt liberally into their CD or DVD player, or cassette deck. As soon as such an item gets onto my bench, and that unmistakable smell comes wafting out, I gently sigh, and start writing out the paperwork saying "Sorry, BER due to having been WD40'd ... "

Arfa