I have Jeep roof rack cross bars on the top of my Commander. The front crossbar seems to be held in place pretty well and the rear one is loose and slides back and forth when I drive. I notice that there is a key slot on each end of these cross bars. Is a key needed to tighten or loosen these cross bars? If so, where would I find another key, as I did not get one with the purchase of this vehicle? Or if anything I would like to just take them off and put a roof rack of my choosing on. Any help or suggestions would be much appreciated. Thanks in advance!