Have a 1966 260B, the front passenger seatback will not stay in the full upright position. The cams are good, I've tried adjusting the stops for a tighter fit, have no excessive play anywhere I can find, found the release handle rubbing on the lower seat cushion so "adjusted it" so it no longer makes contact but yet when you sit in the seat and put your weight against the back rest you can actually watch the release handle move until it pops out of the full up detent to the first recline position. Could excessive lubrication cause this? The thing that really puzzles me is the first detent is where the problem stops(no pun intended) and the cam lobe at this point isn't very high but it holds the seatback in this position just fine. I bought new seat cams but don't think this is the problem. Has anybody run across this and what did you do to fix it? Hate having to brief my passengers to be wary and if the seat pops back don't panic, just afraid they may reach out and grab the controls at a very bad time, not that there would be a good one. Thanks for the help.

When did the problem start? Whatever changed right before that is the likely cause.

As I recall there are also screws around the hinges that go in laterally from the sides. They join the seat frame to the hinge. I have had those screws back out. it occurs to me that if a screw was backed out far enough, pressure on the seat back could make it "pop" over the screw. May not be the cause but worth verifying.

- Charles

Thanks Charles and Pat. I'll recheck the screws although I don't remember seeing any backing out. Pat started months ago, I'm in the process of training for my instrument ticket and my instructor who is not a big guy by any means was just sitting there and all of the sudden the seat back pops out of the upright detent and once it started it has continued, sometimes when I'm climbing out of the pilot seat I'll brace my arm against to backrest and that alone will cause it to pop back. I've had the pilot seat do it to me also but it hasn't had any issues lately. I use to rent an arrow and the seatbacks also did this, no clue what was the cause with them, just assumed rental plane and worn hardware.

There should be two springs that hold the cams tightly in the upper cam position. You should feel substantial resistance to moving the seat reclining handle CCW, when viewed from the seat.

Thanks Kristin will take a look at these.

Kristin you were right. The spring next to the release/recline handle was broken. Took me a bit to figure out how to get the new ones on but they did the trick. Thanks to everyone for their input helped me out a lot.