Anyone know anything about manually locking front hubs
 

Got a 96 Sidekick Sport with manually locking hubs. Right front hub wont lock so I can't get 4WD. Anyone know anything about these. Happened last year and I was able to jack up the wheel and spin it while locking it and it then locked. Not this time. Feels as if the knob is not connecting to anything. It moves with very little pressure compared to the left front hub.

Most lock-out hubs have a simple dog clutch engaged by a spring when the knob is turned. The grease inside has likely got thick and the spring hasn't the power to engage the dog clutch. They're not difficult to partially disassemble to clean and re-grease.

Thanks. Took it apart today and cleaned it up. Now it seems to be working.