Seized Seat Post to Titanium Frame - Page 2

yarbsr02 · #16 05-31-2023, 09:19 PM

Last last resort. I tried all of the tricks for a Syncros aluminum post in an 853 steel IF frame. Eventually cut the post off flush w the frame, drilled and filed the back to match the frame. Original clamp back on and reamed for a 25.4 post to fit the I.D. of the original post. Worked out great…once I made peace w leaving it in place. Thomson is thinner on the sides so maybe not round enough to be ideal for that approach. Good luck!

dddd · #17 06-01-2023, 01:52 AM

Sawzall works great but you have to avoid any contact near the clamping slot or at the opening edge of the seat tube.
One also has to be aware of the tool's stroke length, so as not to have the tip of the blade catch the opening!
The cut only needs to reach up to the height of the bottom of the clamping slot (but should be clocked well away from the slot, and away from any hole leading to the top tube).

First determine the post depth, then find (or narrow down) a blade to reach in far enough. I've narrowed the blade's section height using a bench grinder when the seatpost was thick-walled and/or very long (I couldn't find a long and slender enough blade at the store).

The cut has to be continuous and fully to bare titanium metal, else the post will remain tight in the tube. A sharpened and bent spoke can probe the cut for any remaining aluminum bridging.

The blade won't start to cut against the inside of a steel or titanium seat tube. There has to be high enough concentrated contact pressure for the blade to even begin cutting at steel or titanium, and which won't happen on the inside of a tube unless you contact the opening edge of the tube.

The cutting process takes but a few minutes if the blade (at least the teeth near the tip) are kept sharp.

The post will twist out with only modest torque after it has a continuous clean slot through it.

Heating and cooling the post (in lieu of cutting it) can be beneficial at initiating motion along the length of the bonded area. The temperature changes expand/contract the post lengthwise, which does break most of the length of the bonded area. The post does remain very tightly gripped however by the now-highly-compressed corrosion buildup between the post and the seat tube, as I have twisted away at such compression-gripped seatposts for hundreds of cycles of back and forth twisting just to get the post to come out a few millimeters.

The freezing technique is proven to loosen the grip on the post somewhat, depending on how cold you can get it. Having it covered in frost after dry ice application does make twisting it back and forth noticeably easier, while any friction-induced heating (from twisting efforts) makes it harder to turn.

fmradio516 · #18 06-01-2023, 11:20 AM

Quote:

Originally Posted by BobC

I had this problem & tried pretty much everything listed above.

I recommend this only as a LAST RESORT

1. Cut the seat post horizontally (recommend as close to top as possible). Give yourself as much seatpost as possible to work with.
2. take a sharpie and mark the edge of where the seatpost is in relation to the frame.
2. Take a vise grips & clip it on with one claw in the seat post/ one out (the vice grips be in parallel to the seat post). Recommend the large claw be on the outside. Make sure it is VERY tight.
3. Take a hammer and strike the vice grip clamp parallel to the seat post and away. BE CAREFUL. Don't strike the frame.
4. Check the sharpie mark to see if it has moved.
5. Repeat as necessary. Shouldn't need to do this too much once you get movement.

Oh yeah. I had an old Scwhinn wind trainer I used to hold it.

Like I said. LAST RESORT. But it worked for me. Not good times though.

I have pictures somewhere. But they are not pretty.

Tip for making the vice grip tight.. clamp it tight-ish where you want it, then take a hex key to the back of the adjustment screw. Can even use an impact drill on low. it tightens the grip even more..

DWF · #19 06-01-2023, 12:54 PM

Same as mentioned by others:
1) penetrating oil
2) heat/cold
3) twist on old seat attached

Some tips that worked for me, learned from other Paceliners:
1) hang bike upside down, remove bottle cage, spray penetrating oil through cage mounting hole to get oil to the bottom of the seatpost and soak.
2) a paint scraper heat gun can be used for the heat cycle if you don’t want to use your kitchen stovetop (or if you don’t have a gas stove).
3) for the twisting the seat post method in the absence of an available vice, I jammed a crowbar under the seat space to get better twist leverage.

Good Luck!

fmradio516 · #20 06-01-2023, 12:56 PM

thats a nice flite!!

FriarQuade · #21 06-01-2023, 01:19 PM

There's a lot of things that can work, but I've started just reaming the old post out with an adjustable reamer. By the time these problems walk through the door of the tool shop people have tried all the things that have been suggested and failed. The reamers have never let me down though.