Manual switch to control vacuum hubs ?

[oldfordman]

Have a 99 Ranger 3.0L, auto trans, 4WD with the vacuum hubs. 95K miles. So far the 4WD and vacuum hubs are working great, previous owner was a ford mechanic and he rebuilt most of it. QUESTION- Can I hook up a toggle switch to manually control the vacuum hubs? I'm thinking of a 3 position switch, where center position would be "OFF" (no power to the vacuum solenoid), then the other 2 positions would be hubs "ON" (power to solenoid), or hubs "AUTO" (or factory setup). This would let me engage the hubs w/o engaging the transfer case so I can spin all the parts a few times a month to keep things lubricated. (The wife is tired of me running the 4WD on her lawn). I could also run the thing in 4WD low range w/o the hubs engaged for slow moving when backing up the trailer, etc. If it was just the solenoid, I would go ahead and wire it up, but I understand they get a pulse every 40 seconds or so, and I don't know if the PCM gets involved in this, seems like it is hooked into everything else in the truck. Thanks for any input

 

[martin]

I was under the impression that the vacuum hubs work like a retractable pen.
there's an article somewhere on this site about making them manually operated.

 

[partsguy84823]

Funny story, so I was sitting at work yesterday, and I had this same idea. Weird huh? Anyway, they do work kind of like a retractable pen. One pulse of vacum locks the hubs in, another pulse unlocks them, and on and on we go. So really all you would need is an momentary contact switch to lock/unlock them.

I had actually thought about making work like this... Xfer case in 2wd -- hubs are always unlocked. If you put it into 4wd the hubs are locked by default, but you have a push button and an inticator light to unlock the hubs. If you then switch into 4low the factory setup doesnt pulse the hubs, so they remain unlocked unless you press the button again which would lock the hubs. But say you are in 4wd and you unlock the hubs, then switch back to 2wd, the factory setup would cause a pulse which would cause the hubs to be locked in 2wd, so set a micro-controler up to create one more pulse to ensure that the hubs are never locked in 2wd, and are by default locked in 4wd.