Bicycle Mechanics - Sadde height locked :(

I bought a used Centurion Crazy Point a few years ago, however I never got around to using it because the saddle was too high.

When loosening the fastening bracket, the saddle does not move no matter what amount of force I put on to twist it. The saddle bar is aluminium and I believe the bike frame i steel, so there might be a chance of corrosion involved.

Question is, what can I do to fix it? Can I do it myself or do I need any special equipment?

Thanks in advance,
Nicolaj

you can do it yourself , it just a matter of time , from a minute to weeks to get the post out , the question is how bad is the corrosion ? use some kind of oil , like WD-40 and others you can find in a hardware store . spray into the frame where the post meet , hit the post with a rubber hammer , try turning the post ,let sit for a hour or two ,try again until it come out .

Tried that already without luck. Might try again, but the oil isn't really seeping in.

It sounds like it's frozen in due to corrosion. This is very common with aluminum posts and steel frames, especially in areas of rain riding and/or high humidity.

Removing them is a major undertaking, with people having (and not having) success with ammonia, penetrating oil (USA brands, Kroil, liquid wrench, etc.) lots of torque using a pipe wrench or a vise, and/or cutting it off and slotting it (slow and difficult) so it can be collapsed and removed in sections.

As I said this is a long difficult process and if you're unsure of your skills, I suggest visiting a local shop and getting a quote for the job. Otherwise there are lots of threads covering the issue elsewhere on this forum, or on the internet, so I'm not going to try to duplicate all the approaches. Search "frozen aluminum seatpost (https://www.google.com/search?q=frozen+aluminum+seatpost&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=fflb)" and read about what's worked for others in the past.

can you remove the bottom bracket ? ,if so try spraying from that end . also try ammonia in the place of the oil . the kind you buy at the hardware store , not the supermarket . it stronger . if this doesn't work then you have to cut it out .

Phosophoric acid (aka regular CocaCola) can be used on oxidized aluminum. Sounds weird but works when some other techniques don't. Penetrating oils work best on steel to steel corrosion problems and are less predictable on bimetalic locks. I've only had one seat post that I had to cut out and that was a long process, even with power tools. What worked best was using a long, thin medium-toothed blade on a demolition saw. I used a well worn blade which had enough bite for the aluminum but skated when it hit steel. I'm sure I could still have hurt the frame fairly easily but I went slow and inspected with a flashlight frequently. I only made one cut clean through the seatpost, the others went nearly through. After a total of four cuts I was able to use a waterpump (channel lock) pliers to bend the post in on itself and twist until it finally popped free.

If you can get it at least twisting even a small amount, I used sandpaper on the seat post in the slot in the seat tube. Drop of oil, twist a tiny bit and repeat all the way around and it loosened up enough to pull up an inch, and repeat. It eventually came out.

can you remove the bottom bracket ? ,if so try spraying from that end . also try ammonia in the place of the oil . the kind you buy at the hardware store , not the supermarket . it stronger . if this doesn't work then you have to cut it out .

can you remove the bottle cage bolts and spray in from there?

can you remove the bottle cage bolts and spray in from there?

Of course. The object is to get the stuff inside so it can soak between the frame and post working up from the bottom. In many cases I've drilled small holes in the post and injected ammonia that way.