So after scoring my Master f/f, I realized that the fluted chromoly seatpost was stuck.

It didn't look too bad, so after a week-long soak in WD-40, I gave the post a few straight-down whacks with a sledgehammer. This broke the rust free.

Usually after the sledgehammer trick, it's smooth sailing. Not this time.

First I tried to twist the seatpost with the seat. No dice. Next I tried Vise-Grips, and finally a pipe wrench. Nope.

The next option was to drill a hole horizontally through the post, insert a steel rod to make a T-handle, and twist the post like that. Usually, it works. This time, I got a little back-and-forth motion...and then the post broke off.

I now had about three inches of post left. So, plan B.

First, I got some Kano Kroil (thanks for the tip Ted Carl) from Amazon.com and soaked the post with that. Left it overnight.

Today, I got out the pipe wrench. But, I didn't want what was left of the post to get crushed by the wrench (which is inevitable). So, here's my new tip: insert something into the post, so it doesn't go flat. I used a 1/2" Craftsman ratchet extension.

With the post now solidly filled, I started using all the leverage that the pipe wrench offered me. Stomped on it a couple times and heard "CREAK!"

Yes! The seatpost is turning.

A few more minutes of patiently applying torque with the pipe wrench (along with the rust-eliminating effects of the Kano Kroil) and the post was out.

But, if I hadn't inserted the ratchet extension, the post would have been squashed flat, or broken off, within seconds.

Here's a pic of the setup after I got the post out of the bike:



And here's the Master, sans seatpost. As I type this, the rearend is taking an oxalic acid bath...

Cool....

remember you can put Kroil inside the post too, and then spin the frame upside down and eventually leave it with the post horizontal, and that way it can work its way in from the bottom AND the top....

Kroil rules. I've been using it for years.

Doug

Bolt a stem to your seatpost, insert forks over the stem and twist, works every time.

Kroil, the oil that kreeps!!! Awesome stuff!!!

Lots of good tips here. Thanks!

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!

I have the exact problem described above.
Trying to remove an aluminum UNI seat post from a 1981 TEAM MONGOOSE frame that was in Hurricane Katrina for a few weeks then sat for months before I was reunited with it.
I have been working on it with a dremel tool an hour or so at a time.
I will get to a point that I can not get any deeper into the tube.
I'm hoping it will be deep enough to use a shortrened seat post to build the bike as a NON-rider (for the most part anyway).
I know this is a HALF___ed way to do it but it will not be a SHOW bike and will never be sold.
Other than this the frame is in decent shape, but of coarse does not have the original blue coating any more.

Old trick. Run the frame where the seatpost is stuck under hot water in the bath tub for about 20 minutes. then it will come out easier than any blow torch or drilling method ever will.

I just got my 1980 all original Blue Mongoose Motomag last Friday. It was a sweet score off ebay and took over 2 weeks to get through customs... Canada is difficult on this sometimes.... Anyway, this bike is total time warp! It looks liked some kid rode it a few times and then deep sixed it in the back of some shed for 27 years! Everything is 100% original. Two crazy challenges though (other than the typical rust and decomposition etc...) 1- The original Mongoose frame pad and bar pad - having never been removed - have "rotted into the metal" and actually began pitting the frame and cross bar!!! Crazy! Once I media blast them and powder coat, they'll be fine I'm sure but a couple more years and they would have eaten right through the metal. 2- Of course the seat post is stuck... I was going to go right to the machine shop tomorrow AM to get it drilled out, but after reading this last post, I'm going to give the hot bath thing a try. Sounds crazy to me, but I'll take the chance to save 50 bones... If it dosn't work, I'll let you know real quick!!!

Good idea inserting the ratchet, I've used the 'soak and bash' method successfully a few times but I've been lucky with no REAL disasters yet

I just tried the 20 minutes under hot water thing on the 1980 Mongoose frame... Nada. I had serious doubts it would make a difference based on what I previously said, but I thought it might be worth a shot, stranger things have happened... Not this time. Anyhow, maybe a 5 to 10 year old stuck post might be parted from it's "tomb in the tube" this way or some of the other ways described previously, but after the amount of time this baby been in, there's no way - this post has not moved for 27 years, it's become one with the frame! I'm sticking with my original reply about the "past the point of no return" machinist drill option. I can't see any other way to deal with something that has bonded at a molecular level, they just can't be separated. One or the other must be destroyed to get them apart (like a super bad marriage LOL). Oh well, off to the machine shop again, time to kill another seat post!

Sadly, the dude at the machine shop is no longer my friend... Claims the drill time on a steel seat post is twice the time for a aluminium post... Ok... No problem, but he used this against me to charge twice for the same job he did on the other bike without asking, notwithstanding his intitial asesment of no problem same job twice bs, had no choice but to pay up because it's a classic NOS 1980 Goose frame but whoa dude... If this was high school, I'd drop ya! Gimme the frame and be gone! Nickel and dimin' on a classic American 70's Goose rebuild... Should be a law against it... Many a machine shop... Only one American classic, Mongoose... You wil not stop me, unfriendly angry machine-shop guy... LOL!

Great tips, thank you , they just had a 78 Mongoose with one stuck in it as well on ebay.

Here is what I finally ended up with...

RECAP-Stuck UNI Al. seat post in a 1980 Team Mongoose frame due to Hurricane Katrina and not getting to it in months after the storm.

I tried all above methods except the machine shop option.

Solution...
I used a dremel tool to cut down into the seat post frame tube a little at a time.
A little at a time over a couple weeks.
I got down into the tube about 5 inches and could not go any further.
With about 3-4 inches of seat post left in the frame, I simply BEAT(!!!!) the remainder of the post down untill it bottomed out. It's new home.
It's not the ideal way to solve the problem but I will keep this bike forever and I can still install a new seat post as far down as I want.
Once the bike is built it will not matter one bit it's still in there.

On to further restoration...