Know it is a tonnes of treads like this on this forum but all of the treads I found missed some information which would help even more. So this is an attempt to gather some of the information on how to fix the common problem on the first gen LS400 with the reclining on drivers seat not working as it should. In this tread is also a short description on how I fixed this problem on my car.
If the drivers seat on your car only reclines on one side (left) this tread is for you.
First I read trough this 2 treads which has a lot of good information in them:
A note on the last tread from LOC. You don't have to remove the seat from your car to fix it.
1) Followed the first 2 steps in the first tread.
2) The problem in my case was that the splined shaft didn't move. The splines on the shaft was destroyed as can be seen on the picture below.
Instead of trying to superglue my plan was to change out the shaft. The art nr on the shaft is 72501-30050 and it is really cheap.
3) Continued to dismantle the seat. To be able to remove the shaft you have to remove the top half of the seat. To do this you have to remove the 2 bolts marked on picture bellow with a 12 mm socket on both sides of the seat.
4) It also helps a lot if you loosen all the straps holding the cables in place. See picture below.
5) Now you should be able to lift the top half of the seat up and tilt it forward. To remove the shaft press out the "frame" as showed in the picture below. In the picture the shaft is already removed.
6) Put the new shaft in. The new shaft is slightly longer then the old one. Make sure the both sides of the seat is level when you do this.
7) Make sure the seat works as it should. Then put everything back together again.
Hope this helps. And hope you can understand my not so perfect English. Feel free to come with comments and post links to similar treads.