ghostm42

I managed to buy a used Specialized Allez Elite bike frame, fork and assorted parts for a very good price. Unfortunately, the carbon seatpost is stuck in the aluminum frame. Now, I have a previous post regarding a stuck aluminum stem and a steel frame (which I haven't solved yet). In that thread and in various other threads about stuck parts, I hear people suggest a Liquid Wrench/PB Blaster and ammonia. But that was for aluminum and steel. Is it safe to use Liquid Wrench (no PB Blaster around here) and ammonia on carbon fiber and aluminum? I might end up buying both tomorrow... which should I try first? How long should it be applied? And is household cleaning ammonia sufficient or do I need something stronger?

I've currently only undid the bolt and attempted to twist the attached seat (round seat tube). It won't budge. I did not try any oils or grease, since I heard there could be issues with that. Since this is a nice frame, my last resort is bringing it to the local bike shop and getting them to try. But it gets too expensive if they spend more than an hour working on it.

sch

First get a sacrificial seat heavy enough to have solid steel rails, mount it off center to maximize
torque. Ammonia attacks the layer of aluminum oxide and reduces friction thereby, it also
to a lesser degree attacks the frame itself, but that is a minor consideration. Liquid Wrench
penetrates the crany between the post and tube and lubricates. To some degree the use of
one interferes with the use of the other, though ammonia, sufficiently strong, eg household
Parsons type, is likely to eventually cut through the Liquid Wrench if you use that first.
Remove the BB turn bike upside down and liberally douse the seat tube with your selected penetrant (Parson's ammonia or Liquid Wrench, your choice) and let sit over nite. If you immediately have a bunch of liquid spill out into the seat, then you will just have to dribble some more down the seat tube and rotate the bike in an arc to distribute the penetrant, If the seat post is sealed at the top pour in 4-5 ounces and let sit. Next day flip bike over and pour out remnant and apply maximal torque to the seat, with luck it will break loose. If not find someone stronger for another effort. If you destroy the clamps on the seat post or the seat rails bend/break then plan B is to cut the post a bit above the top of the tube and get a saw blade long enough to reach the bottom of the residual post and cut at least two vertical slots in the post on the inside til you reach metal. You can then start prying the cut up seat post off the seat tube. A bit of cutting into the metal won't do much damage to the integrity of the seat tube as long as you
don't get carried away. A friend spent a week doing this on an AL post in a steel tube, but
he got it out. Carbon should be easier to cut.

mvnsnd

You might also see if you can get the penetrating oil in from the water bottle bolt holes with the little tube that comes with the can. Then rotate as suggested above. When you do get the post out, make sure you clean all the surfaces. I think it is the long term contact that is harmful to the carbon fiber composites.

HillRider

Ammonia used to free Al seatposts from a steel frame attacks the aluminum oxide and to a lesser extent the aluminum itself. In your case the aluminum is the frame so I'd avoid ammonia except as an absolute last ditch method. Try any of the penetrating oils as recommended and the use of a sacrificial saddle is a good way to get more leverage.

wrk101

No PB Blaster where you are located? Here in the US, it is sold just about everywhere, including Walmart and Big Lots. As far as what works, you go through the various options, from least amount of work to the most amount of work. I have been able to free up about 90% of the stuck seat posts I have gotten. But I have one that refuses to cooperate, I've tried all of the solutions including ammonia. Last step is to cut it out, which I have been avoiding (as long as I have other bikes to refurbish, this one can wait).

And household ammonia is worthless, you need to buy the more concentrated stuff. And given your situation, as recommended above, I would not try ammonia anyway. Its really best suited for a steel frame.

ghostm42

Well, I bought Liquid Wrench and ammonia. I don't have the appropriate ISIS BB tool, so I'm going to have to pour the Liquid Wrench in through the water bottle hole. I guess it'll sit in there until I get a chance to buy the BB tool from Niagara Cycle or a LBS (any difference between the $6.xx one and the $17 Park BBT-22)? If this fails, I'm going to either bring it to an LBS and let them take care of it or just sell the frame as is and keep the parts. The 105 RD/FD and wheel alone should be worth more than what I paid. Oh... another strange thing. When I was unscrewing the water bottle bolt, one of them seemed to take the entire threaded aluminum with it (I was twisting CCW... the other bolt came out fine). I take it that this is because the steel and Al welded together as well?

I'll use the ammonia on my other stuck stem steel/aluminum issues (partially since it's a lot cheaper than Liquid Wrench and I don't care for the stem).

ghostm42

I'm actually in the Boston area at the moment. Anyone know where to get PB Blaster around here? I'm without a car, so it's only whereever the train takes me.

531phile 

So what's the lesson here kids? When buying a used bicycle, make sure the seatpost isn't stuck.

ghostm42

Very true, but I would have bought it again knowing it was stuck. Even if the frame and seat tube is trashed, the rest of the components were more than twice what I paid. The better lesson is, When buying a used bicycle, make sure the seatpost isn't stuck... but if it is, bargain further!

MadBuddha1

Well anytime I encounter a stuck seatpost I always strip the frame down to just the frame and seatpost, sure a little liquid wrench wont hurt,, then I go to my local bike shop where they have a high quality repair stand that is bolted into the floor, then clamp the seatpost down as hard as you possibly can and with help from another guy using the frame as leverage twist the frame back and forth one guy on the headtube other guy on stays (this is key unless you are 6'5 and can bench 400#), the leverage of the frame and gravity have proven to unstick the seatpost. One time I did use a crap saddle and piece of steel braced against the stand arm to stop it from twisting in the clamp. Worked for me everytime so far. The quality and stability of the repair stand and the help from the other person are the key.

ghostm42

Just curious, was it a carbon seatpost? I can imagine the twisting method on steel, but carbon is less forgiving. I've added the liquid wrench and attempted to twist a bit some time later. No budging. I suspect the carbon is starting to crack from twisting.

At this rate, it seems like the seatpost is a goner. I'll likely saw it off and try to saw it out. Then replace it with a cheap aluminum post.

slushlover2

Saw it off flush with the top of the seat tube. Use a long screwdriver and hammer to peel the layers of carbon fiber loose. Use a long pair of needle nosed pliers to pull the strands out. I've done this for several friends and it works quickly.

HillRider

This frame seems to have more than it's share of problems. From your description it sounds like one of the Riv-nuts that make up the water bottle bosses came out with the bolt. These can be replaced and any decent bike shop should be able to do it.

MadBuddha1

Yep I did this when I cracked my FSA carbon seatpost in half on my aluminum Klein. Sawing it out works too if you dont have a really nice clamping stand and some help tho too, good luck you should get it out either way..,.

ghostm42

Ok, I was impatient. I waited a few hours with the Liquid Wrench in there and decided to try to give it a twist. I heard a crack... unfortunately, it was not the Al/C bond breaking. I noticed a hairline crack down the carbon seatpost. Since I've lost all my torque capabilities with the seatpost splitting, I decided to just take a reciprocating saw and hack it down. I'm now going to have to chisel away the fibers. I actually got a good amount of fibers sheets out near the top of the tube, but the tube appears to be a good 7 or 8 inches into the seat tube and I don't have a screwdriver or nail long enough to chisel any further. Looks like I'll have to wait until I get a long nail/screwdriver to finish it. But as long as I work at it, this seems like it'll suffice.

The carbon is really bonded onto the aluminum. If I can't get all the carbon fibers out, any harm in getting a slightly smaller seat post, possibly a shim and just call it a day?

ronp6

I have never tried it on carbon to aluminum but aluminum expands and contracts with heat faster than carbon (or steel). My favorite trick for getting aluminum posts out of a steel frame is dry ice to shrink the aluminum more than the steel. The first time I did it I felt like I was pulling the sword from the stone. Applying heat to the aluminum frame should cause it to expand to a larger tube and work the same way. I don't know if a paint baking oven would be hot enough but it should be safe for the paint. Perhaps an engineer could chime in.

ghostm42

I made a half-hearted attempt with that yesterday. I cooled it with ice and used a blow dryer for the heat, both of which are probably less effective than dry ice and an oven.

The CF chiseling idea will have to do for now. But I wish someone would have mentioned the health risk of carbon fiber dust before I went at it. Wish I had used a respirator as I was trying to tear the seatpost apart for the last hour. FYI for anyone reading this and plans on cutting CF... the fibers are similar to asbestos and causes lesions in the lungs if the fiber dust fragments are long enough. Wear an N95 respirator when working on CF.