Does anyone know if a vacuum leak can cause hubs not to lock on a 1996 f150? The hubs will not lock. Someone said it may be vacuum controled but we do not see vacuum line to hub??? Any other ideas?

 

Your 96 has automatic hubs. Your problem is that one of them has gone bad. Replace them with Warn manual hubs available at Advance. You may also need an adapter kit. If your hubs have only three bolts holding the chrome piece on, you need the kit. If you have 5 bolts, you do not.