Howdy,

Like a lot of you I held on to my Mongoose. I live in Montana but the bike is in Florida under my house waiting to be resurected and I hope my son can take it for a spin someday.

What's the best way to remove a aluminum seat post from the frame? Been stuck for 20+ years

thanks,

Monkeypuzzle

if its aluminium it should come out no probs, as it doesn't rust to the seat tube like a steel one. attach as seat if not already attached, secure frame and try twisting seat by and forth gently moving post up as you go.

failing that, spray WD40 down the seat tube and leave over night to penetrate and then try above.

final thing you can try, but as last resort, which I had to do once. gently heat up the seat tube which expands the tube slightly allowing the inner post to be removed.

good luck

Kano Kroil, the oil that Kreeps!

Ford Bronco Method:
Drill about 3 quarter inch holes through the side of the post, about an inch+ apart. Take some rod, or old screwdrivers and stick them throguh the holes. Take some rope or webbing and wrap it around the post/screwdrivers, then tie a loose end to the hitch of a Ford Bronco. Lay a piece of carpet, a blanket, or cardboard, and lay the frame down on it. Take another section or rope or webbing and wrap around and through the BB. Secure the end of the webbing to an immobile object, like a tree or the hitch of a beater truck (preferably a Dodge or GM.) Take up the slack and then reposition the padding. Ease the Bronco forward and wahlah!

I did this. For real.

While we are on this topic... what would be the best chemical for breaking a really strong rust-bond between steel parts? Sometimes WD-40 doesn't do the trick... is there something that will attack the rust better without ruining the parts? Thanks...

[ Don't have a Bronco but can understand how that would work.


Thanks a lot guys, can't wait to get started.



quote name='Faust Wurstkotzenhauser' date='Jan 15 2008, 04:18 PM' post='487065'
While we are on this topic... what would be the best chemical for breaking a really strong rust-bond between steel parts? Sometimes WD-40 doesn't do the trick... is there something that will attack the rust better without ruining the parts? Thanks...
[/quote]

I agree with a few of the posts above. If you can get a seat on it then try soaking with a good penatrating oil and try twisting it out. I got mine out by inserting a sawblade down in the post and cutting in 2 or 4 places. you have to be sure and cut all the way thru the post. I fabbed my hacksaw blade to an airtool which made cutting much easier. I started with a great disadvantage my post was broke off down in side the frame and after cutting it I had to chip it out with a chisel and a pair of needlenose pliers. The main thing is to be patient and take your time, Good Luck

Hmmn I heard a good idea not too long ago:

1. Clamp a Stem on the post (better leverage) and soak post contact area as best as you can with an available Rust Solvent, Then after a few hours of soaking twist post.

If still no movement.
2. Oxalic dip the post and portion of frame, then follow step 1.

I would not suggest cutting or heating unless you are prepared for the casualties...

I've had better luck getting steel/steel to seperate than aluminum/steel. Dissimilar metals will actually bond, like a weld. Try the afore mentioned methods, but you may have to find a machine shop to drill out the post. If so, it needs to be precise, so find a machine shop. I tried with a hand drill, and wasted an old Panda frame






Yup, Kroil. That stuff is awesome. Not usually available in retail stores, (it's for industrial use only), but you can find it on the web. I bought my last can from a tractor website, I think.


Doug

I found a '83 Cali at a flea market and the post was all the way down and rusted solid. I disassembled the bike completely and started spraying pb blaster in every hole that would eventually drain to the seatpost first straight down the post itself, stuff a piece of shop rag in the bottom hole where it comes down into the crank bearing case so it will pool up in there and let it sit for a day or so spraying more in as it seeps thru the rag. Flip the frame upside down and reverse the procedure spray into the small hole you had plugged with the rag and stuff the rag into the top of the seatpost this time, let it sit and keep filling it to keep it full as you lose it thru the rag. You can also spray into the two small holes in the rear triangle(close to where the brake mounts are on a cali anyway) as these also lead into the seatpost tube when it is upside down. I did this for about a week(be patient it won't happen over night) flipping it every day to attack it from each angle. I then put a [pipe wrench on the seat tube and tried to twist on it(I put the frame in a bench vise holding it by the crank bearing case with towels of course and do not crush it!) I noticed it was really starting to tweak on the frame so I stopped and soaked it some more( like 2 more days) I then wised up and got 2 pieces of 2x4 about 2' or so and clamped it in the vice with the boards traversing the whole front part of the frame seat post tube, down tube and top tube diagonally so as to transfer the twisting force thru the whole frame instead of just the crank case or b/b case whatever it's called I'm not to familiar with all the proper terminology yet. I then drilled a 3/8 hole horizontally thru the seatpost and ran a good strong tempered steel bolt thru it about 5" long take a long box end wrench slip it over the bolt head, if you have ever worked on cars you might be familiar with this technique, to use as a cheater bar and crank on it. I found doing it from both directions back and forth until it gives a little. You will know when it happens. Then just work it back and forth as it moves a little more each time. Before you know it "Presto Allakazaam" That mother is home free. You have to say the words for it to work( I think). Then call the guys at the bikeshop that told you not to do it because you would break something and gloat a little. Not to much just a little. Hope this helps someone should work on any frame even if you don't have the 2 little holes like on the cali frame just be patient on the soaking part. Later

Aluminum posts are harder to get out than steel for the reasons listed in above posts. Doing all the lubin' listed above always helps too. I never would put a frame in a vise and take the risk of damaging it. The way to do it is to use an old junk square stem bolted as tightly as possible to the seatpost near the frame, then put then stem in the vise, not the frame! You then can use that big long frame as leverage to twist the post out.

"If still no movement.
2. Oxalic dip the post and portion of frame, then follow step 1.
"

btw, this is in TC's no-no list

I have a thread about my Laguna with a stuck Aluminum seatpost and this was brought to my attention

chemically welded?? Itried all the above so far PB blaster, seat, vice, stem w/fork, won't budge. In the same article from the above quote they say Ammonia will work I'm going to try that next. Let you know.

I can vouch for Kano Kroil. They have their own website and an old school newsletter that I'm sure people on this site will get a kick out of.

That product is unbelieveable. I had an alloy post that seemed impossible, I tried WD-40 and PB Blaster soaking for days. I clamped a stem around it and stuck a long lead pipe around the stem shaft to increase leverage. The alloy post actually started to TWIST around like a churro, I had to stop because it looked like it was going to break! And it remained 100% stuck.

I repeated the same thing with Kano Kroil soaking for about 30 min and it finally broke free.

I know this sounds like a infomercial but really works!

I also used Liquid Wrench too and it didn't work at all, plus it stunk up my whole garage for a week.



http://www.kanolabs.com/

Yep big no-no, 1st it won't do jack to an aluminum post, 2nd on a chromoly post if any Oxylic solution does penetrate the bond it will crystallize and you'll never get it out.

Anyhoo, here's my preferred method. This pic is for illustration purposes only as the seat post on this bike is not really stuck

Clamp an old stem and some forks to the post and turn that sucka out.

An alternative method on aluminum post involves using anti-freeze (yes- the green Prestone stuff you put in your car) to dissolve the bond between the aluminum and the steel. But using the former method should work for you, besides this method is messy and you wouldn't want your dog licking this stuff up off the garage floor.

"Seafoam" I have had FANTASTIC results with this stuff.
or "PB Blaster"

This topic is always coming up... I've been to hell and back on this and many, many educated people exchanged knowledge with me on this.

As I only restore bikes that are all older than 20 years, I can only repeat what I had posted here last year which I hope will help and save some people some cash and possible damage to their frames:

"Depending on the length of time a post has remained set in a frame, there can be many different degrees of "stuckness"... All the methods I've read about so far are pretty good but won't make any difference once it's "past the point of no return". The "point of no return" would usually be after 15 to 20+ years in most cases. This is especially true with aluminium posts stuck in a mild steel or chrome moly frames. At this stage, the two (post and post tube) will usually have already bonded at a molecular level. Basically, they become one. No amount of turning, twisting, soaking or insane hammering will work at all. Often the frame will simply shear or split. Then it's way too late... When it's at this point, the home bare blade sawing inside the post will not work either. The only fool-proof method to remove a post that has "bonded" with the frame is to drill the offending post out. The drill bit has to be long enough and the exact width as the post but not wider than the tube. Any decent machine shop will be able to do this usually under 1/2 an hour. Depending on their rates (most between 50 -100 bucks an hour) it shouldn't cost too much. I just had one taken out of my 78 Goose which I rescued from an abusive home... Worked like a charm! Hope this helps!"