Try pulling the latch/lever up a little, then attach the knob. It should still lock the backrest in place. If not, I suspect the rear cover isn't fully seated against the seat ?

 

I've tried attaching it while the lever is at the top and the knob still wont slip over the lever for it to be secured to it. I've snugged down the seat back as far as it will go, its almost like the lever component is too far recessed into the seat, I don't even know if that is possible?

 

Not really, unless the lever was bent ? On the right in the pic below shows the latch mechanism. Did you replace the rear cover (seat back) on both seats or just the passenger side ? Hard for me to say what's causing the problem. You'll have to compare the drivers side with the passenger side to see what the difference is and why one side fits and the other doesn't. Sorry, that's about all I can offer...

 

Im going to take it apart this weekend to see if I can see anything obvious, I appreciate your advice! PS I replaced both seat covers at the same time.

 

Just a follow up, took both seats out and first off the seat tracks didnt appear the same. However the drivers side knob that did fit had a washer used as a spacer where the lever screws onto the seat mechanism to push out the lever a bit. I did the same to the passenger side and the knob now fits. Probably not the way its supposed to be done but it looks and works fine now.

 

Hey, if it works :thumbsup:

 

Is it possible that the seats are from a 67 that had the metal backs which were much thinner steel than the plastic is? You said the drivers already had a shim to make up the difference.