If the traveller is not running freely, check the balls inside as well. They do wear out and require replacement.
Be careful if you take the car off. You need a piece of track to run the car on to.

The split tail is tied off to a small eyelet on each side of the centerpoint of the beam. Implementing this will gain you a few centimeters but it will not center 100% anyway. Best solution there is so far though.