[BeetleBetty5]

I am experiencing a problem with the Seatback Adjustment in my 1999 VW Beetle. I have turned the "wheel" on the outboard side of the seat cushion to where I want the seat back adjustment to be. However, over a period of time, the adjustment is lost, and the seat back goes to the far back position. Is something needed or what do I do to "set" the adjustment.

Thanks.