Seat dropper posts are a great addition to any mountain bike. They are also quite expensive. Before you shell out a chunk of cash on a new seatpost, try to get the old one back in shape for more riding.
Regular Seatpost Lubrication
As the seatpost is used, the lubrication is used up and the post can get sticky and not operate smoothly. This can be prevented by regular application of grease. This is an easy thing to do and will keep the seatpost operation smoothly. The first step is to unscrew the collar at the top of the lower part of the seatpost and slide it up the upper post. Clean all the dirt from the collar seal, seatpost and the threaded part of the lower seatpost.
When the post is clean, apply some lightweight grease to the top of the lower seatpost. You want to use the slipperiest lightweight grease you can find.
After applying the grease, screw the seatpost collar back on the lower part of the seatpost. Be careful not to strip the threads. Tighten the collar down; running the collar loose will not make the seatpost work better but it will wear out the bearings quicker. Cycle the seatpost up and down a few times and clean up any excess grease.
That's it, back on the trail with a smooth operating adjustable seatpost.
Repair Loose Seat
You may notice that there is some "side to side" play of the saddle. Eventually, the seat will loosen up and the seat will spin all the way around. If you have this problem, you fix it yourself and be back on the trail within hours. If you notice the saddle is loose, disconnect the remote cable from the lever under the seat, spin it counterclockwise and remove the seat clamp assembly from the upper part of the seatpost.
Leave the seatpost clamped into the bike frame and no need to remove the saddle from the seat clamp assembly. Clean the threads of the seatpost clamp assembly and the upper seatpost tube. Lay the bike down on its side. Screw the seatpost clamp assembly back into the upper seatpost and turn it a couple times. By doing this, when you apply the threadlocker to the seatpost clamp assembly, none of the threadlocker will get into the upper seatpost tube.
Apply threadlocker to the exposed threads of the seatpost clamp assembly. Loctite 242 Threadlocker is a good way to go; strong enough to keep the seatpost clamp assembly from coming loose, but you will be able to remove the seatpost clamp if necessary.
Turn the seatpost clamp clockwise until tight; don't over tighten it, that's what the threadlocker is for.
Clean up the excess threadlocker, let it set up for a few hours and you're finished; back on the trail.
Complete Seatpost Service
The KS adjustable seatposts require regular lubrication and maintenance to work properly. There are instructions here on how to lubricate the seatpost while it is still on the bike, but it's a good idea to take the seatpost apart, clean everything up, check to see everything is working properly and give all the moving parts a good lube job. How often this type of maintenance is done depends on how much you ride, the riding conditions and if the seatpost is sticking, binding or hard to operate. At least once a year, if you ride a lot, especially in dusty or wet conditions, two or three times a year might be more appropriate to keep the seatpost working smoothly and prolong the seatpost's life. It's not hard to do and doesn't really require any special tools.
If you have a remote seatpost, use a 2mm allen wrench to loosen the cable lock nut and pull the cable out of the remote lever. Check the end of the cable; if it is frayed or crushed, it's going to be hard to get it back into the little hole on the remote lever, so you are probably going to need a new cable. If you don't have cable cutters, you should take the old cable down to the local bike shop and have them cut the new cable to the right length for you. A new cable should only cost a couple bucks.
Loosen the seatpost clamp and pull the seatpost out of the bike frame. No need to remove the seat. Be sure the seatpost is fully extended.
Unscrew the seatpost collar.
Turn the seatpost upside down and you will see a nut, lock washer and the seatpost end cap. These will all need to be removed.
Remove the 11mm shaft end nut and lock washer.
Next, the seatpost end cap has to be removed. This may be the hardest part of the whole procedure, so use caution that you don't damage anything. You are going to need something to hold the seatpost. A strap wrench can be used, but if you don't have one, you can use a vise. Use a rag around the seatpost so you don't scratch it up with the vise and don't clamp down too hard! The lower part of the seapost is basically an aluminum tube, if you crush it, the seatpost is shot.
If you have a pin spanner wrench that fits the end cap, that's perfect. Turn the end cap counterclockwise and spin it out. Most likely you won't have a pin spanner, but you can use a pair of needle nose pliers. Stick the nose of the pliers in the end cap holes and turn counterclockwise. If it doesn't want to come out, use a large screwdriver between the plier arms, push in on the pliers so they don't pop out of the holes and lean on the screwdriver to break the end cap loose. Unscrew the end cap and remove it from the seatpost. The end cap is also made of aluminum and if you're not careful, you can damage it.
After the end cap is removed, pull the seatpost apart. There won't be anything in the lower part, the upper/inner shaft should have the setpost collar, silver DU bushing and three guide bushings on the shaft. These guide bushings are what keeps the seat from spinning while allowing the seatpost to move up and down. Remove the guide bushings from the grooves in the shaft and slide the Du bushing and seatpost collar off the upper shaft.
At this point, the seatpost is completely disassembled.
Here's the disassembled seatpost showing all the parts. Time to thoroughly clean all the parts. Check for scratches or any other signs of damage. Except for the 11mm nut, lock washer and bottom out bushing, you'll have to contact KindShock if you have any damaged parts that need replacement.
Click on the photo to see a larger picture with all the parts listed.
Time to start putting the seatpost back together. Apply a light layer of grease to the upper/inner seatpost shaft. Just like with regular lubrication, we are going to use a slippery, lightweight grease. Slide the seatpost collar and DU bushing on the seatpost shaft. Put a little grease in the grooves in the seatpost shaft and stick the guide bushings back in. The grease should hold them in the grooves. Make sure the guide bushings are fully seated in the grooves.
Apply a liberal coating of grease to the upper/inner seatpost shaft.
Apply grease to the roller bearing at the top of the lower seatpost. Work the grease into the bearings with your finger. Put a dab of grease on a long screwdriver and grease the inside of the lower seatpost, especially the slots where the guide bushings will go. Stick the upper seatpost shaft into the lower seatpost tube. Carefully line up the guide bushings with the slots in the lower seatpost tube. If you left the seat on, it will help you line things up. The numbers that show you how far the seatpost goes into the frame are on the rear of the seatpost, point the seat towards the front and line up the guide bushings and the slots. Don't force anything. When everything is lined up, the two parts will easily slide back together.
Push the DU bushing into the top of the lower seatpost tube and make sure it is fully seated.
Make sure the bottom out spacer is on the long shaft coming out of the bottom of the upper/inner seatpost shaft. The end cap will fit over the threaded shoulder on the end of the shaft.
Screw the end cap into the lower seatpost tube with the pin spanner or needle nose pliers. No need to crank on it, snug is fine. Put the lock washer on and tighten down the end nut. Tighten up the seatpost collar over the DU bushing.
Put a thin layer of grease on the seatpost and stick it back on the bike. Connect the remote cable if you have one, test it out to see if the seatpost is operating smoothly. If everything works, you're good to go.