well, I am having a problem with my 76. I was missing the lower and upper lock linkage rods. replaced them, but I cannot get the lock to engage. there is very minimal movement on the piece that the key linkage rod goes into. even when I try to raise or lower it by hand and not the key. any thoughts? the latching works fine, but I want to be able to lock this thing up to finish the build out. any advice would be great.