Stuck Seat Post, Again

As a dumpster and flea market bike fan I've had my share of stuck stems and seat posts. After
searching the archives and making inquires, I tried the ammonia and bench vice method of stuck stem
removal (aluminum stem/ steel forks) on two formerly stubborn bikes (Thanks Andrew). This worked for
me where other methods (penetrating oil and bench vice) had previously failed.

Last summer I picked up a nice Bianchi MTB with a very stuck seat post (aluminum seat post/ steel
frame). The post was inserted into the frame as far as it could go. Fortunately the built in seat
post clamp could not enter the frame, so about 2 inches remains exposed. My previous stuck stem
removal methods failed on the seat post. In fact, attaching the bike upside down in a bench vice by
the seat post, lubricating, and twisting only resulted in torquing the frame. No movement of the
seat post.

I read Sheldon's comments about stuck seat posts, and decided to wait for a cold cold day to try to
free it. The theory being that aluminum contracts more than steel in cold. It was less than 20
degrees today. I tried the bench vice. The seat post freed enough to rotate fully inside the frame.
Try as I might, I was unable to make any headway towards actually removing the post. Twisting and
hammering failed to yield any noticeable removal.

I'm hoping for even colder weather. Any other suggestions, short of the laborious process of
carefully cutting it out with a hack saw blade?

Thanks, Larry

 

I haven't tried this on a bike, but a source of amazing cold temperatures is freeze spray (not sure
what the official name is but it's used to test intermittent chips and the like) from an electronics
store (like Radio Shack). Maybe if you arrange your method of gripping the post so you can get
freeze spray into the inside of the post. Or make friends with someone who has liquid nitrogen,
which is easy to transport in a stainless steel thermos (keep upright and make sure it is NOT sealed
tightly). The freeze spray is great on a q tip as a substitute for an MD's liquid nitrogen or dry
ice as well. (Use with caution.) ALso, I bet if you can let it sit in a walk in freezer for a little
while. Keep in mind that extreme cold makes some metal brittle, so be careful.

I make no representation that the above methods are safe; you will have to use your own judgement
and really think about what you're doing unless you want frostbite, exploding thermoses, frozen
eyes, etc.

Another idea, if you can get at the inside of the post, is to get water or ice in there and then
heat up the frame.

I'm assuming you've let some penetrating oil sit in there for a long while. SInce it's already
moving maybe you just need more lube.

Lawrence Fieman wrote:
>
> As a dumpster and flea market bike fan I've had my share of stuck stems and seat posts. After
> searching the archives and making inquires, I tried the ammonia and bench vice method of stuck
> stem removal (aluminum stem/ steel forks) on two formerly stubborn bikes (Thanks Andrew). This
> worked for me where other methods (penetrating oil and bench vice) had previously failed.
>
> Last summer I picked up a nice Bianchi MTB with a very stuck seat post (aluminum seat post/ steel
> frame). The post was inserted into the frame as far as it could go. Fortunately the built in seat
> post clamp could not enter the frame, so about 2 inches remains exposed. My previous stuck stem
> removal methods failed on the seat post. In fact, attaching the bike upside down in a bench vice
> by the seat post, lubricating, and twisting only resulted in torquing the frame. No movement of
> the seat post.
>
> I read Sheldon's comments about stuck seat posts, and decided to wait for a cold cold day to try
> to free it. The theory being that aluminum contracts more than steel in cold. It was less than 20
> degrees today. I tried the bench vice. The seat post freed enough to rotate fully inside the
> frame. Try as I might, I was unable to make any headway towards actually removing the post.
> Twisting and hammering failed to yield any noticeable removal.
>
> I'm hoping for even colder weather. Any other suggestions, short of the laborious process of
> carefully cutting it out with a hack saw blade?
>
> Thanks, Larry

--
Lincoln Ross NOTE ADDRESS CHANGE: [email protected]

 

Lincoln Ross wrote:
> I haven't tried this on a bike, but a source of amazing cold temperatures is freeze spray (not
> sure what the official name is but it's used to test intermittent chips and the like) from an
> electronics store (like Radio Shack). Maybe if you arrange your method of gripping the post so you
> can get freeze spray into the inside of the post. Or make friends with someone who has liquid
> nitrogen, which is easy to transport in a stainless steel thermos (keep upright and make sure it
> is NOT sealed tightly). The freeze spray is great on a q tip as a substitute for an MD's liquid
> nitrogen or dry ice as well. (Use with caution.) ALso, I bet if you can let it sit in a walk in
> freezer for a little while. Keep in mind that extreme cold makes some metal brittle, so be
> careful.
>
> I make no representation that the above methods are safe; you will have to use your own judgement
> and really think about what you're doing unless you want frostbite, exploding thermoses, frozen
> eyes, etc.
>
> Another idea, if you can get at the inside of the post, is to get water or ice in there and then
> heat up the frame.
>
> I'm assuming you've let some penetrating oil sit in there for a long while. SInce it's already
> moving maybe you just need more lube.
>
> Lawrence Fieman wrote:
>
>>As a dumpster and flea market bike fan I've had my share of stuck stems and seat posts. After
>>searching the archives and making inquires, I tried the ammonia and bench vice method of stuck
>>stem removal (aluminum stem/ steel forks) on two formerly stubborn bikes (Thanks Andrew). This
>>worked for me where other methods (penetrating oil and bench vice) had previously failed.
>>
>>Last summer I picked up a nice Bianchi MTB with a very stuck seat post (aluminum seat post/ steel
>>frame). The post was inserted into the frame as far as it could go. Fortunately the built in seat
>>post clamp could not enter the frame, so about 2 inches remains exposed. My previous stuck stem
>>removal methods failed on the seat post. In fact, attaching the bike upside down in a bench vice
>>by the seat post, lubricating, and twisting only resulted in torquing the frame. No movement of
>>the seat post.
>>
>>I read Sheldon's comments about stuck seat posts, and decided to wait for a cold cold day to try
>>to free it. The theory being that aluminum contracts more than steel in cold. It was less than 20
>>degrees today. I tried the bench vice. The seat post freed enough to rotate fully inside the
>>frame. Try as I might, I was unable to make any headway towards actually removing the post.
>>Twisting and hammering failed to yield any noticeable removal.
>>
>>I'm hoping for even colder weather. Any other suggestions, short of the laborious process of
>>carefully cutting it out with a hack saw blade?
>>
>>Thanks, Larry
>
>
Not cold enough? Try pouring boiling water over the seat tube while the bike is vised up.

Flame me if my idea is lame, Kenny Lee

 

Do you have access to a freezer big enough for the bike? Had a similar problem trying to fit
an inlet manifold onto a triumph stag V8....... Bunged it in the freezer, and contracted
enough to fit fine.

 

On Wed, 15 Jan 2003, Lawrence Fieman wrote:
> > Also make sure the seat tube is not distorted, this could be trapping the
> seat. It looks good to me.

Well, I hope that if bent it is so in the section sticking out. Else ...

Sergio Pisa

 

"Sergio SERVADIO" <[email protected]> wrote in message > > > Also make sure the seat tube is
not distorted, this could be trapping the
> > seat. It looks good to me.
>
> Well, I hope that if bent it is so in the section sticking out. Else ...

There is no evidence of a bent seat post, as the seat tube is not misshapen. Neither visual nor
tactile inspection reveals any defect of the seat tube. Regards, L