'91 S10 4X4 help?

[1QUICK85]

I got a '91 beater S10 with 4x4 that I need help getting the 4x4 to work right. I have been looking for vacuum diagrams like crazy online cause 2 of the vacuum lines are disconnected, but can't find anything.

This what I do know about the 4x4:
It has the shifter on the floor for 4x4.
It has the 4x4 servo located under the battery tray that is suppose to pull the cable to engage the front diff.
There is 2 vacuum hoses coming from the servo under the battery tray and they are just lying there.

So, I was going to start with at least getting everything hooked up like it should be, but I can't find any vacuum diagrams online. I have no idea how this 4x4 system works. How is it suppose to function? Obviously there is a reason the 2 vacuum lines are unhooked, so maybe once they are hooked up correctly I will know whats wrong with the system.

Do you think if I was to put vacuum to those 2 lines that it would engage the 4x4?

Any help or a link to vacuum diagrams would be great! I would post this on the S10 board, but I never get a good response over there and I know this board is full of GM diehards that know their shat!

TIA, Nick.

 

[SFITurbo]

Vac switch on the t case routes vac to the ball thing under the batt, pulling the cable to engage front axle. (switch goes bad and you will suck tranny fluid into the motor to be burned) Some people convert to a cabel system like a hand choke.I have the diagram somewhere, I'll look for it if you really need it.

 

[1QUICK85]

So, those 2 vacuum lines should go to the transfer case then. I'll have to get under there and look. Maybe if they are unhooked from the switch then the switch could be bad?

I did find this(cable pull like you said): DIAMOND - Welcome to my little world.

^Seems easy enough to do.....I might just do that.

 

[SFITurbo]

At the switch..one is vac source and the other goes to the actuator ball, so when the t case is switched to 4 hi/low vac is ported via switch to the actuator. It is a PITA to replace if bad, worse than the speed sensor! Cable or a vacuum switch on the dash would be ALOT easier to fab up IMO.

 

[1QUICK85]

Thanks for the help. I'm going to try the cable pull mod and then I shouldn't have to worry about anything besides the cable.