I'm not convinced anything is actually broken. What may be more of the problem is a piece might be missing that connects the release lever (the part behind/under the headrest) to the locking arm (the piece with the notches that locks into the back seat).

When I had it apart and it was locked in, I was able to take a needle nose pliers and slightly twist the locking arm and it would release. The release lever isn't connected any way to the arm, it is just floating free. That's why I'm not sure how the release lever connects to the locking arm.

The release lever has about a 2 inch "U-Shape" at the end and I am assuming that should be connected to something that makes the arm turn slightly for the release or is something broken off the release that connects it to the arm. I appreciate your time in helping with this!!!!