MY doors have a problem with latch action, on center pivot there is a bolt top and bottom which is operated by mid position lever mechanism. The top bolt lifts into place but the bottom bolt only moves a few mm, either had become disconnected or snapped from centre lever mechanism.To access do I remove top and bottom nylon bolt guides and unscrew bolts [they seem to be connected by a threaded bar.] then remove lever, to free mechanism in centre for inspection?