yuyax

Well, I have a case of the stucked alloy seatpost (SR LaPrade) inside a steel frame (Columbus SL). The seat post seems to be the correct side. No bulging noticed on the seat tubing.

The seat and seat post clamps have been removed. The side of the LaPrade seatpost is nice and flat. I put a large adjustable wrench to see if I could move something. Nothing, not even an a mm. I am able to pry the ears of the seat cluster but the seatpost is stuck about 85% inside the frame


I read Sheldon's tip about ammonia. My questions:

1- Do I squeeze 100% ammonia or a diluted version?

2- How long do I let it sit before I can try again?

3- Any harmful effects of ammonia to the steel frame? Neutralization necessary?

3- Any other tips, help?

Thanks

broomhandle

try liquid wrench. just drizzle it down a few times, should come free.

ofofhy

I would suspect Sheldon is talking about household ammonia, as the more concentrated ammonia would be a serious breathing hazard. I got a facefull of ammonia gas this past year (thanks to an incompetent labmate) and it was not fun, with the exception of the hot doctor lady. You can only get the more concentrated stuff through chemical suppliers.

yuyax

Yeah, I sprayed some Liquid Wrench yesterday. I will try again today.

Sheldon does say that Liquid Wrench or oils are pretty much useless when dealing with Aluminum oxidation hence the ammonia

Djudd

I used this technique last year for seatpost a stuck for about two years (I didn't see a reason to "unstuck" it until an overhaul of the bike):
It took about two days and was pretty painless, I used undiluted ammonia poured through the bottom bracket shell in an overturned bike. I let the ammonia sit as I used the saddle to twist the post with my feet on the underside of the saddle. After a few tries, over a couple of days it twisted out. I cleaned the inside of the tube with a rag and soap and water.
good luck

T-Mar

Frozen seat posts are one of the most frustrating situations facing a home mechanic. What it will work and how quickly, depends on the time and conditions that the post has endured. In a couple cases, I have tried all of Sheldon's tricks, to no available. The seat posts had to be cut off and reamed out. Good luck!

nick parry

First, try hammering the seat post IN a little. This sounds mad, but it may break the oxide "weld" and allow penetration of oil etc. Then try to twist the seatpost out. If hammering in produces no movement, decide how badly you want to keep the seatpost, then saw it off about 2cm above the frame and using a hacksaw blade cut through the walls of the seatpost, being careful not to damage the inside of the seat tube. Make 2 cuts at about 70 degrees from each other (you can use the slot in the frame as a guide for one of them) you do not have to cut right through, then using a narrow chisel between the seat tube and the seat post bend or snap (depending on the material of the seat post) the segment out. Once relieved, the rest of the seatpost will release with a little chisel work. I have had the first work twice and the second work on at least 3 occasions that I can remember. We did once manage to remove a post by heating the seat tube with a torch, but obviously this is only any use if you are doing a respray.

broomhandle

i would do what Djudd said, turn it upside down and go thru the BB, try liquid wrench and if that dosent work, go with ammonia.

liquid wrench has to set overnight.

luker

Clarifying, once more, use undiluted household ammonia. Anything else is dangerous.

peripatetic

I've got a stuck seatpost that I've tried to use Liquid Wrench with several times to no avail. I've also tried using it on a stuck crankbolt to no avail. I think it's kind of worthless for things like this. A couple of people recommended PBlaster to me, and I have a can, just been too lazy to try it. I think it's worth the purchase just for the packaging.

Take the rest of this as mere info being passed on, not necessarily any sure-fire solutions...

Anyway, someone advised me that once you've added tons (and he said, "tons," just spray gobs of the stuff down around the post) of anti-seize, you can take off the saddle, put a wooden board on top and pound down a bit to loosen it. Once it's loose, wiggling it out should be easier. I'm going to try that next.

Using anti-seize down the bb sounds like a good idea, too, but then one has to deal with the PIA of removing the drivetrain, with no sure remedy promised. Or, someone else told me that I could put the anti-seize inside the bottle cage holes (unf. my Miyata frame doesn't have any!) That sounds like a slightly easier approach.

Report back if anything works for you, this problem has been hanging over my head for months, and since it's such a supremely frustrating proposition, I've effectively abandoned it.

One Q: Assuming one gets a post un-stuck, can it be used again with some proper cleaning/lubing, or is that just asking for more of the same heartache? Does one need to do something to remove any oxidation inside the seattube of the frame or outside of the Al seatpost?

divineAndbright

I also have a frozen seat post on my ccm fleetwing. I tried wrapping a monkey wrench around the seat post to twist it with every last ounce of torque I could muster, also tried the blow torch to the seat tube part of the frame method, other than some monkey wrench groove marks indented in the seat post and burn marks on my frame nothings changed.. it is indeed frustrating. I also thought of flipping the bike upside down and pouring something in through the BB, but was never really in the mood to remove the crankset. But alas, looks like I'll just have to do that.. sometime before winter (I plan this to be my main winter/snow riding bicycle).

lotek 

I haven't had to deal with this issue but I've heard that
Kroil (like liquid wrench?) works very well on stuck seatposts.
Same technique as the ammonia.
As for removing cranks and BB, I'd rather do that
(and gives me an excuse to overhaul the BB) than
risk damaging the frame.

Marty

shiftinjon

take the front wheel out. leave the rear wheel in. turn the bike upside down. clamp the seatpost in a vice. put one hand on the rear dropout and the other on the headtube. get a friend to help with this if possible. twist. seatpost free.

USAZorro

I had a stuck stem on a frame I got back in March. I had to resort to plans C through E before all was said and done, but I won. I imagine the same technique I used could work for a seat post as well. Note that this will trash the seat post though.

Cut the post off about 4-5 cm above the top of the frame, and make three cuts into the post (sawing into the opening of the tube with a hacksaw that has one end exposed) evenly spaced at about 120 degrees. Cut as far into the seat post as you're comfortable, being careful not to cut into the frame tubing. Once you've made the cuts, clamp the seat post with a vise grip right above the seat tube. The idea is to get the post to separate a little from the tube all the way around. Once this is done, try to twist the post. If it moves, you're home free. If not, apply more penetrating oil/ammonia/liquid wrench, or whatever. Give it another day and try again. If it still doesn't want to budge, give the post a couple good raps with a hammer, and try again. If this doesn't work, repeat the process for a couple more days. If worst comes to worst, you may have to do what T-Mar did and have the post reamed out. I'd be very surprised if it came to that though.

Good luck.

mollusk

Those pesky bi-metallic reactions! The problem is having an aluminum alloy seatpost in contact with a iron alloy seat tube. The corrosion oxidizes the aluminum to aluminum oxide and there you have it. That's one of the reasons why you need to grease your seatpost on a regular basis. Aluminum alloy stems in stem forks are even worse.

A "trick" that works sometime is to flip the bike over and pour a can of Coke down (up?) the seat tube. The phosphoric acid in the Coke will work on (dissolve) the aluminum oxide and if you are lucky it will work on it enough. Diet Coke also works. Ammonia, on the other hand, works on the aluminum. You can get REALLY strong ammonia from a blueprint supply store, but that stuff can be very nasty. Only use that in a very well ventilated area, like outdoors on a very windy day. The ammonia shouldn't do much to the steel frame, btw.

duane041

Well, if you are not planning on reusing that seatpost, you could get a drill and drill through the seatpost on opposite sides (drill pilot holes with small bits first), making the holes large enough to fit your biggest Phillips screwdriver through (they have round shanks). Run the screwdriver through and start crankin'. Might try something called "PB Blaster" on the post first. I think that stuff is available at better hardware stores. And it is light years better than the 'other' penetrants out there.

peripatetic

So what do all of us losers with stuck seatposts (past and present) think about using a combination or sequence of Coke/phosphoric acid followed/preceded by ammonia/penetrant? And for what it's worth, I've always greased my seatposts; the problem for me is that the previous owner two removed wasn't so assiduous.

PS Anyone else notice that there's another "stuck seatpost" thread in the Mechanics section? Such a provincial forum, so little crossover. Wonder where else we could sneak one in...Commuting, maybe? Foo?

lotek 

Here's an example of what not to do:

yuyax

Well, good news folks.

What I did first was to spray liquid wrench all over the place and let it sit for about two days. Then I clamped the top of the seatpost on a bench vise (frame is upside down) and attempted to rotate the frame around it. At the beginning, the seatpost felt like it was one with the frame and I was wondering if I had to go the ammonia route. After a few tries, the seatpost gave and I was able to get it out.

I didn't see or notice aluminum oxidation or at least it wasn't very obvious to me. The seatpost was inserted almost 90% into the frame.

I am glad I got it out without any major damage. The seatpost came out of a Nishiki Maxima (columbus, campy, etc) frame that I will listing on Ebay pretty soon. When I get a chance later, I will post pics in the Nishiki threads.

Thank you for your tips and help.

mike

In desparation, I have done this. It is "OK", but you can twist the seat post into a pretzel without success and then you are really screwed.

Another method is to put a junk seat on the seat post. Tighten the seat to the post tight as a Muthaaa..
Sit on the floor and put your feet on the underside of the seat. Hold onto the frame, pull and twist the frame while pushing on the seat with your feet.

Try this "Jack Lalaine wanna-be" method first before you twist the seat post in a vice.

divineAndbright

Here is my jerry-rigging concept; this is for anyone whose seat is too low, stuck and they are needing to raise it to avoid a case of sore knees when riding, and doesnt mind doing things a bit differently.

1. Go find another seat post
2. hack saw it to appropriate length (you'll be sleeving it over the original seat post)
3. sleeve it on over original seat post
4. its going to swivel like a seat post in the tube with no nut to tighten it so you can:
a) try drilling a hole through em both and insert a bolt/nut
b) hammer the post down over the original one where it begins to get bigger.

I guess the seat post might crack on option b, but I opted for that route and it worked great, problem solved!

Skip Magnuson

Ouch - I hate the idea of sawing my Campy alloy seat post off just to get it out of my 1971 Italvega. I have tried Liquid Wrench for about 3 days and no movement. I'm now on the third day of the amonia treatment (the amonia goes somewhere down the seat tube). I guess I have all winter to get it loose as I do have another road bike (I wonder it it's seat post is stuck too).

Skip Magnuson

Final chapter - after a week soaking with PB Blaster I took the bike out the garage and made wood blocks for each side at the top of the seat post and tighten in a bench vice. With just a gentile tug of the top tube in both directions the post came free (after maybe 20 years in a fixed position).

Motofan

I'm going to go out and grease the seatposts on all five of my bikes right now!!!

cyclotoine

I had to cut a seatpost out too. Bought a jabsaw and cut the two slots till I had two peices of seatpost..hours it took. it finally came free. The post was too big and hammered on or something... You can feel the ridge in the seattube where the post ended... ARG!!! it was painfull. it was the only think that worked after tons of ammonia and liquid wrench I felt like I would bend the frame if I pulled any harded with the seatpost in the vice. I only succeeded in snapping the post... which led to the saw method.