Rear seat reclines on its own
 

I have been searching around this morning and cannot find an answer to this. My drivers seat (and passenger I think) seem to recline as I drive. They are manual seats, and it seams like the action o the seat back bouncing up/down a little as you drive over bumps causes the seat to recline. This means I have to reach back and wind it back up every so often.

I would think there is some kind of washer or spring that is suppose to hold some tension not he seat back mechanism so it does not recline as I drive. Any one have a clue what part I need to fix/replace to prevent this from happening?

Well this is frustrating. No one know why the stock manual seats might recline on their own as you drive and hit bumps, or what might be adjusted/repaired to prevent this? Seems like it would be a common problem as these seats get older. Hmmm

My drivers seat recently seems to do same thing
 

Anyone have any tips on this ? My drivers seat seems to do the same. Never an issue for 14 years but upholstery shop recently had seats apart to redo bolsters on seat backs.... any kind of adjustment for tension or locking? All works ok but seems like I have to reset the seat recline back up every so often

There is a somewhat circular tensioning spring in behind the adjustment knob. If you go to the Porsche website and check out the parts diagrams for your year you can see an exploded illustration of a seat. It is part number 91152157100.

Beyond that, I'm afraid I don't know. Maybe you can remove the knob, expose the spring, and tighten it somehow, maybe by bending it.