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will.s

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Discussion starter · #1 ·
My son's bike is a ~2014 Yeti SB66 carbon frame with a KS Lev dropper. The dropper has started rising on its own, and I want to service or replace it. The problem is when I tried to remove the dropper from the frame it would not budge. I bought this bike used and don't know what was done when it was installed. Any ideas on how I can get the dropper out without damaging the frame?
 
Kroil works VERY well. The only product that works better in short burst of time is 50/50 acetone/atf (which you need to shake, and will eventually separate...even once you've applied it).

I had an unloved garbage-picked frame [steel] with a stuck seatpost/bottom bracket [aluminum parts]. The seatpost was not budging, so I hit it with Kroil, and left it for a week. When I came back, a minute of twisting/hammering on the bottom of the seatpost, and it was out. Likewise, the bottom bracket; I barely moved the cartridge, then sprayed the joint with Kroil. You can literally see it bubble/wick into the gap. Afterwards, a few minutes with the breaker bar, and it was out.

That said, temper your expectations. Aluminum corrosion is a 'B', and you can't really work with heat, since CF composite is largely temperature stable. You might try a product called "Freeze Off" (you can get it at the auto parts store--sold by CRC) shot in through the bottom bracket shell. The cold caused by the chemical reaction could shrink the aluminum post, break some corrosion, and allow it to wick up to the seatpost clamp.
 
Take out the bb , turn it upside down and poor some coke down the seatpost tube. Let it set for a while and try again. The acid in the coke will release the post.
 
Discussion starter · #10 ·
I have been hitting it with penetrating oil for over a month now and no movement. There is no access to the seatpost from below due to the infinity link. I am going to take it to a local shop this winter after the riding season ends and see if they can get it out.
 
Take out the bb , turn it upside down and poor some coke down the seatpost tube. Let it set for a while and try again. The acid in the coke will release the post.
Isn't that just carbonic acid that is present in any fizzy "water"?
 
I think you need to applying increase amounts of jandle to release it.
If penetrating oil does work then try heating and cooling the post. You cant go too hot because that will damage the carbon. But if you heat it up enough to expand and then cool it enough to contract that might be enough.

I would head the post with a heat gun until almost too hot to touch. Around 60 deg C. The smack and ice back around it to cool it down. then heat back up. Leave the while frame in the sun with penetrating all then give it a crack. I like Milehi's idea of posting in a vise and twisting the frame. That might be enough to crack the corrosion or dirt free. Do that in conjunction with heating/cooling and a tone penetrating oil might be what the doctor has order.

PS I had to do this recently with my should axle. It seized in the hub. I did all of the above and had to apply more
 
I think you need to applying increase amounts of jandle to release it.
If penetrating oil does work then try heating and cooling the post. You cant go too hot because that will damage the carbon. But if you heat it up enough to expand and then cool it enough to contract that might be enough.

I would head the post with a heat gun until almost too hot to touch. Around 60 deg C. The smack and ice back around it to cool it down. then heat back up. Leave the while frame in the sun with penetrating all then give it a crack. I like Milehi's idea of posting in a vise and twisting the frame. That might be enough to crack the corrosion or dirt free. Do that in conjunction with heating/cooling and a tone penetrating oil might be what the doctor has order.

PS I had to do this recently with my should axle. It seized in the hub. I did all of the above and had to apply more
Maybe a hair-dryer to avoid the "going too hot" part? That's what I always use.
 
I'm reposting here from an old thread. the gamechangers are points g) and h) . Hope it helps.
......................................................................................

Found some great suggestions here, and I will just share the trick that worked for me. Stuck dropper on carbon frame.

First, throw away those damn grip pliers ! Don't ask how I know.

Second, if you do not have a machine shop nearby to get a soft clamp as recommended by the great Peter Verdone do as follows
a) Spray Wd40 or other penetrating lube at the seatpost/seattube junction,
b)Rest for a few hours
c) If you feel so inclined, turn the biike upside down and spray the lube on the seat tube wall trough the BB (I didn't)
d) Rest for a few hours.
e) Get an old stem (31.8 handlebar clamp) . Ideally with a thick, 4-bolt faceplate.
f) Make an appropriate shim using a coke can or any other soft metal thickness so that the stem clamps has a perfect grip to the seatpost
g) Clamp the old stem to the stuck seatpost, as low as possible toward the seat post, and as tight as possible.
h) Using a rubber mallet, alternatively strike the stem until the seatpost gets unstuck
i)Done!

Cheers
Fab
 
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