bikehellion

Apologies if this has been asked before, but the quick search didn't yield anything.

I have an unknown 80's Bianchi frame (CrMO) that has a stuck Aluminum seatpost. I am talking about really, really stuck, where saddle rails were touching the top of the seatube. After LBS unsuccessfully tried removing it, I tried to give it a shot by stripping down all the parts and clamping the seatube in a vice -- and then slowly twisting, turning and this worked. I have it about 1 inch out, and will complete the job by end of the week.

Now for the questions

1. After removing this, what is the best post-treatment of the inside of the seattube? Clean it with a rag, and then just grease it well?

2. Seatube has cracked a wee bit just below the braze-on seatpost collar ears (i'll take a photo when I get a chance). While I am sure that this is not a major issue, what would be the best strategy for resolving this? I was thinking of grinding down the collar ears, welding the cracks, and then using a separate seatpost clamp.

Cheers,
BH

Andrew R Stewart 

Excepting the crack... Clean up the seat tube ID to raw metal. Honing or emery cloth on a long shaft. Then apply a phosphate solution (navel Jelly), let dry then Frame Saver the frame (not just the ST). Finally grease the new post and maintain better in the future. Andy (looking to see what the crack really is like).

maddog34

!: get a metal rod about 3/8" in diameter...

2: hacksaw a slot to 2 inches, right down the middle of one end, then radius the end of the rod to prevent gouges inside the seat tube....

3: get some emery CLOTH...180 or 240 grit... hardware stores will usually sell it by the foot, or you can find it in sheet form, and cut your own strips, two inches wide...

4: slide a 6 inch section of the emery cloth strip into the slot...

5: install the rod/emery into a drill chuck of your variable speed hand drill...

6: clean your seat tube only enough to remove the rust/crud, but NO MORE than absolutely needed! some seat tubes are REALLY THIN.

7: add a bit of grease to hopefully prevent future rusting/sticking.

8: go ride your bike after you install the new post, and whatever seat you select.

bikehellion

Thanks Andy & maddog34! Really appreciated. Still waiting to get some time off work to finish pulling out the seatpost. I will follow your procedures afterwards. Bike was a gift from one of my coworkers, and I am still deciding should I keep it as a 6 speed (Shimano 600 grouppo - really amazed by how good these older groupsets are) or convert it to singlespeed.

Seattube crack the next post.

bikehellion

corrado33

You should convert it to single speed and sent me the 600 groupset.

Bike tinker man

Nasty cracks, be very careful they do not expand them when removing the rest of the seat post, assuming the bike is stripped BB out, bike upside down, you can pour various release agents etc down, & be very careful working it out don't rush it, taking it back in then out to help release it, not just straight twist pulling out. Maybe few days even.

Then you can decide how best to treat the cracks once its out, & see inside.

bikehellion

What would you as a "release agent"? Were you thinking in terms of ammonia that a lot of people use for stuck seatposts, or more of a mineral oil lube-type-of-thing to help with lubing the seatpost. As I said, I can get it moving, but it's going really slow and it's making awful screeching sounds at every turn.

I know a lot of people frown upon WD40, so what would be the next best thing to drip down the fluted seatpost and lube it up?

Cheers

corrado33

Honestly if you can get it moving I'd just spray whatever lube you have (penetrating lube if you have it) and force the post out. I'd not want to wait too long on a post that's half stuck.

Bike tinker man

I've had several seat post stuck normally after hour or two they free up, but about 8 years ago I really had a classic stuck one, I stripped the bike up-ended it, then used an old sacrificial saddle which was clamped in a vice, the trouble is if you clamp the seat post its liable to buckle or crack, & it may add to your problems. It took me a weekend to slowly turn the bike work it up & down.

I use various release agents like WD40 to me these are to be applied then cleaned off afterwards, I would not open something spray in WD40 then close it up & use it, so take your time, don't rush it, hydraulic oil is also very thin finds its way in everywhere.

Where the seat post clamp bolt goes through - have to tried to widen this slightly very carefully with a chisel or equivalent, it will help spread the neck section.

You cannot afford to let those cracks migrate further.

Andrew R Stewart 

very often small length binder slot base cracks can be eliminated by a larger "hole" filed in the slot's lower end. Actually I know of no guide line other then tradition to how large this relief hole can be. Andy.

Bike tinker man

I fully agree with Andy above, but once its out yes you should drill a very small pin hole at the end of the crack, this is an engineering trick to stop cracks migrating but you are looking at something no bigger than 1/32" drill bit & the average electric drill chuck will not hold them, you need a pin chuck to hold the drill this then goes in the normal electric drill chuck.

Nu2Miele

The "drill the crack" trick...

I agree completely about drilling the end point of a crack with a tiny diameter drill bit. If stripping the bike down for a repaint..heat the seat tube up (once the paint has beem stripped) with a torch, then use a HOT soldering iron.on the crack...silver solder the crack and the drilled hole. Use a small ball hone (electric drill driven) to remove any burrs, or a "bastard file" (a rounded file on one side, a flat on the other) and clean up any solder inside the seat tube. So many don't truly understand why things crack. Often due to impurities in the metal, or thermal cycling , which can set up tiny stress risers. Any additional shock or stress then has a chance to set up a crack.

My suggestion: regardless of what you do to get the seatpost out of the seat tube, is to grease the seatpost well before reinstalling it, or use an anti-seize compound like Permatex 133H, or a copper based one such as Permatx 9127. Undo and move the post a few times a year, re-applying which ever you use.

Regarding the stuck seatpost, I too have one that I need to remove and am frustrated, but thankfully it is fluted and I should be able to remove it given enough time with whatever miracle oil I can get.

Limper

Instead of grease, I use "anti-seize" compound (like Nu2Miele mentioned). I think the copper-based compounds are for high-temperature applications such as mufflers/exhaust parts for engines. I think something like grease, being as it's slippery, would make it necessary to tighten the parts more than anti-seize, which is more sticky than slippery. I'm not loyal to any brand, I happen to have some Loctite anti-seize in the shop.