maybe I'll have better luck here, anyone?
http://www.chevelles.com/forums/showthread.php?t=136382

no retainers to my knowledge. The center tip fits into the seat bottom bracket, and then the hinge on the outer edge of the seat back fits in place with a friction fit. That is how mine went in and I've not had any problems with them coming loose.
Brian

Thanks ,
After playing with the seat for an hour, I believe whats happened is the foam padding put in when the seats were recovered is to thick... and when the seat is pushed forward it's forced out due to lack of clearance between the seat bottom and back.
thanks again
Seb