Giee4

Hello, i'm new to the community and to biking in general. My problem is, i was trying to lift the bike saddle up, but i couldn't because the seatpost was stuck, so i unnattached the saddle. Right now i want to reattach it, but i can't understand how. I've been thinking and watching videos for some days, and every saddle attachment mechanism is different to mine. Here are some pictures.

. - Album on Imgur

bulldog1935

of course the square nut goes on top, and the clamp side with the shorter rails should have a square recess in it that the nut drops into.
The clamp side with the longer rails goes on bottom and should be a convex side on it that slides in the concave side on top of the seatpost casting.
Of course the single bolt goes all the way through from bottom outside of post to the square nut.

Giee4

Yes! it worked! Thank you very much, you're a hero! Now I need to unstick the seatpost, which is not going to be easy, it seems to be stuck quite hardly.

bulldog1935

my first though is spray boeshield let it soak in a few days and come back

SkyDog75

Stuck seatposts can be a royal pain. If you were to search the forums, you'll find plenty of discussions. Sometimes it just takes (reasonable) force and persistence. Sometimes a penetrating oil like Kroil or PB Blaster (and letting it sit for enough time) helps. Some people have reported luck with CRC Freeze-Off.

If you don't have any luck with non-destructive removal methods, you can destroy the seatpost to remove it. If it's a steel frame, you can remove the crankset, flip the bike upside-down, and pour some lye into the seat tube. Lye won't harm steel, but it'll dissolve aluminum. (Which creates hydrogen gas, so do it in a well-ventilated area without any flame or sparks nearby.) Or you can cut the post off above the frame and use a hacksaw blade inserted into the cut-off post to (slowly) cut a slot. The slotted seatpost will be easier to remove. Be sure to leave enough post to grab with your tools of choice (vise, vise grips, pipe wrench, etc.).

As for why it happened... Is it an aluminum post and a steel frame? When steel and aluminum are in contact with one another, they're subject to galvanic corrosion. To cut down on galvanic corrosion and prevent your seatpost from getting stuck, coat the post with grease to act as an electrical insulator.

cny-bikeman

If you have a bike co-op nearby take it to them for assistance, or have a bike shop do it for you.

bulldog1935

essentially what you have is white clay aluminum corrosion product and red rust binding it.
Penetrating oils and also Boeshield chemically reduce and shrink those corrosion products. It may take time just for it to penetrate.

Giee4

This is a picture of the saddle and the seatpost. Yes, steal bike and aluminium post.Imgur: The most awesome images on the Internet

Update: I tried using some wd40 and some boiling water aswell. It was impossible to move it at the beggining but now i am able to move it to the sides, but while doing so, there's a very loud noise that sounds like a screaming cat.

Bill Kapaun

More lube!

fietsbob

Search " stuck seat posts" = Bike Forums - Search Results

JohnDThompson 

If you have access to a sturdy, bench mounted vise, you can clamp the cradle part of the post in the vise and use the bike frame itself as a lever to loosen the post.

cajunpedaler

We had a stuck seat post on a tandem one time. We used "aerokroil". We applied it and tapped the seat post. Eventually the aerokroil worked its way and the set post was freed.

okane

Enough with the wd 40 which is a lite duty lubricant. Blaster, Liquid Wrench, Freeze sprays will help, not WD 40