Bicycle Mechanics - seat post sslides down..how to stop?

My mt bike seat post will not stay put.....It seems to want to slide down about 1/4 inch or so then stays put.....I need to know what I can do to keep it where I need it.. It is aluminum bike & post....well greased and tight seat bolt binder.

Provided the seat post is the correct diameter, I would venture a guess that your clamp is too wimpy. I had this same problem on my surly long haul trucker's stock stainless steel clamp. I could tighten it down with a LOT of torque and the post would still slip.

I went out and bought a salsa lip lock and the problem immediately disappeared. There apparently is a huge difference in clamping force among seat post clamps, which I didn't think about before I had problems. The lip lock takes very little hand tightening to get a rock-solid clamping on that post.

http://www.google.com/products?hl=en&q=salsa+lip+lock&wrapid=tlif12845508708822&um=1&ie=UTF-8&ei=3LCQTMnrEIX7lwfAy4HkAQ&sa=X&oi=product_result_group&ct=title&resnum=1&ved=0CCYQrQQwAA

I welded mine in...

If the binder assembly is replaceable the above solution is what you need. If not you will need some more creative solutions. Need a good pic from the back of the seat post and binder.

I've had good success with using carbon assembly paste on slipping components. I've also found that replacing the clamp can do the trick too.

I was going toask about the new carbon paste. Do I need to clean off all greese first ? Is the paste acting like greese but with more sticking power?
Thanks for the idea.

I suspect over greasing.. .. My Folding bike has a plastic bushing, sliding the seat post is integral to the fold ,
and it slipped [ used bike ] so I got a 2nd QR band

Took the lip out, (half round file) and flipped it over and tightened it on top of the other one,
around the seat post directly ..

Slipping stopped.

seat post sslides down..how to stop?
Fill the seat tube with rocks?