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-   -   Stuck Seat Post! (https://www.bikeforums.net/bicycle-mechanics/551494-stuck-seat-post.html)

0llie 06-13-09 02:04 PM

Stuck Seat Post!
 
Right, i've had this problem for a while, basically my seat post is stuck in the frame and i can't get it out. I tryed everything from Sheldon Browns help page thing... anyway finally i got to the last method (everything before failed) and i cut the seat post to find that it wasnt hollow, basically if you look at it, its abit like a "Peace sign" so i can cut it out, and its very hard to even get the hacksaw blade through the gaps.

I was wondering wether it is possible to actually drill it out, because i think thats my only option? could you suggest where to go to do this, or any other options to getting it out.

My bike is a Raleigh Road bike, white aluminium frame and aluminium seat post. Im not sure what model it is, but there is something which says R1 700c. I've been sorting this out for a few months and still havent got the post out, and it seems to be taking forever!!

Thanks in advance,
Ollie.

peripatetic 06-13-09 02:28 PM

Multiple threads on this topic, do a search under my screen name. Drilling involves gradually increasing the size of the bits. It's time-consuming and you need the right bits. Many bike shops can do it, though I think they charge somewhere around $40-$80 or more to do it. Another approach is using lye to dissolve the aluminum out. That also takes time. I think user timcupery did this with a stuck stem (far less metal involved) that was successful. Good luck.

0llie 06-13-09 03:03 PM

Sorry, none of this helps because i've tryed it all before as i have already mentioned! Is it possible to drill out the seat post or what?

norwood 06-13-09 07:18 PM


Originally Posted by peripatetic (Post 9095638)
Multiple threads on this topic, do a search under my screen name. Drilling involves gradually increasing the size of the bits. It's time-consuming and you need the right bits. Many bike shops can do it, though I think they charge somewhere around $40-$80 or more to do it. Another approach is using lye to dissolve the aluminum out. That also takes time. I think user timcupery did this with a stuck stem (far less metal involved) that was successful. Good luck.

OP's bike is an aluminum frame...

Is it stuck solid or can it move a bit? Continuing with the hack saw blade may be your best bet. If it moves a bit, you may be able to cut off as much as possible and drive the rest back down into the seattube. Then use a new post over it. But this could backfire too.

rideabike 06-13-09 07:37 PM

I wouldn't take it to a bike shop. I'd take it to a machine shop. They have more equipment for this and could tell you what it would cost.

To answer your question, theoretically you could drill it out, but you would have to do so with a drill press and a vice to hold the bike so it wouldn't move. That's why I suggest a machine shop.

wrk101 06-13-09 07:58 PM

+1 Machine shop. Just get a cost estimate first, as a replacement frame may be cheaper.

Lye is a really bad idea when you have an aluminum frame bike. It attacks the frame and the seat post.

If you have a drill press and a steady hand, you could try to at least enlarge the hole in the seat post so thqat you can get a hacksaw blade to work. I would NOT attempt to drill into it without a drill press.

Panthers007 06-14-09 12:29 AM

I would try checking the 1/2 million other threads on this same subject. You will find how others came to solve this situation. Without resorting to drilling and other invasive measures.

Regards lye - Sodium Hydroxide, NaOH - this chemical does eat aluminum. It's what it does for fun. I'm a chemist and can attest that using NaOH on aluminum is a very bad idea - if you don't want your aluminum-frame compromised structurally. If you use NaOH to clean the surface areas of components, do so quickly and rinse the parts off immediately. Then apply a weak acid to thoroughly neutralize any remaining lye. Vinegar - 5% Acetic Acid - is a good choice.

drafters65 06-14-09 01:39 AM

take a torch and heat the seat post up... as an auto mechanic that is what i do when i need to loosen a seized bolt on a car. I don't know how aluminum reacts to heat so you should wait for someone elses opinion on this. GL

pstock 06-25-09 12:51 PM

Miraculous Stuck Seat Post procedures
 
1 Attachment(s)
If I am not too late, here's the solution (or rather two solutions, one simple, one more complicated.)
this week I found myself facing two impossibly stuck seat posts on bikes I'd bought on ebay. If I didn't get 'em unstuck, the frames were worthless.

A LBS here in Toronto directed me to a fellow named Martin Heath who runs a shop called Cine Cycles. I was told Martin was a specialist in unsticking seat posts (and indeed, when I met him he told me he'd yet to meet a seat post he hadn't been able to unstick.)

One of my frames was aluminum and so there might have been some alu-alu corrosion. I dosed it with Ammonia (per Sheldon Brown's 15 steps) and then Liquid Wrench penetrating oil. the other frame is steel but the SP was way way stuck in (see photo) I just did penetrating oil in this one.

Anyway, Martin's worst case solution (which avoids heat which he says usually trashes the frame) is to drill a hole in the undersid of the BB hole, chop off the seat post (leaving an inch or so exposed, with the center hole open). he then threads a long (3foot) bolt up the seat tube and out the seat, with a nut above and below the seat post. then he uses a giant round weight (it weighed about 20lbs) to hammer UP from the underside of the seat tube.

He didn't have to use this ultimate solution on mine.
His first step is to use a very solid bench vise as follows:

- let the oil penetrate for long enough (I had only let it sit overnight)
- remove the seat (and the wheels).
- invert frame and stick the bent part of the seat post (the bracket or whatever) in the vice and crank it down TIGHT. (he used a 3 foot pipe to crank the vice arm.) I guess this procedure doesn't work with seat posts that don't have the little attached bracket.
- turn the frame gently and once it budges a bit, start pulling up as you twist it back and forth

- he then bored out the seat tube to make it smooth.

It was miraculous. After just a minute or so both of these were free. (I am surprised that Sheldon Brown didn't include this procedure in his suggestions.)

good luck.
Peter

JohnDThompson 06-25-09 12:55 PM

I'm not sure why Sheldon didn't include it, but I've seen seat tubes destroyed by careless application of that procedure.

CliftonGK1 06-25-09 01:06 PM


Originally Posted by pstock (Post 9166136)
His first step is to use a very solid bench vise as follows:

- let the oil penetrate for long enough (I had only let it sit overnight)
- remove the seat (and the wheels).
- invert frame and stick the bent part of the seat post (the bracket or whatever) in the vice and crank it down TIGHT. (he used a 3 foot pipe to crank the vice arm.) I guess this procedure doesn't work with seat posts that don't have the little attached bracket.
- turn the frame gently and once it budges a bit, start pulling up as you twist it back and forth

+1

This was the method I used to get the post unstuck from a 1988 Trek 400 which I salvaged from the dumpster last winter. Some WD-40 as an overnight pre-soak, then use the whole frame as the lever while the post was clamped in place. I took some calipers to the stuck post, and it appears the previous owner had forced in a post which was too large. Must have hammered that thing in there.


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