Driver seat problem
 

I'm now having a problem with my driver seat. After around 18,000km of driving, it starts to have an annoying sound like the nuts and bolts underneath seem to loosen up. I've tried to remove nuts and bolts and screw them all up tightly again.

However, it didn't solve the problem so I started to wonder is there something wrong with my seat.

The sound only occurs when I go over the bumpy road, fast cornering , and heel and toe.

If anyone has encountered this issue before please give me some suggest about how to solve this issue.