question about 4X4 vacuum

[GRONK]

Jim,  I have set these up several ways with great success.  90% of the time, I eliminate the vacuuum ball and all the "stuff" attached and go direct with the RED source line to manifold vacuum on the intake.

I have never had an issue doing it this way on Jeeps or on Eagles.  When the engine is running, there is vacuum.  Which ever way your selector switch is positioned, will be the way it works.

I started doing it this way when time after time I was troubleshooting Jeeps and Eagles that had bad, missing, weak/cracked otr otherwise inoperable vac systems.

This method has always worked and worked well for me.

My understanding is the vac res is there for the 4x4 system to give you up to 2 shifts when the vehicle is not running.  It actually will work if you vac system is stock and working, you can select 2x4-4x4 a few times before the vac wears out w/ the engine not running.

With pulling direct manifold vac to the switch, you will only be able to switch if the engine is running.

My $.02

[carnuck]

Actually, it's so you have vacuum when climbing a hill or high torque situations (like pulling a trailer up a grade) so the front axle and tcase don't un-shift on you (happened to me and took out a NP229 in an FSJ)

[jim]

It wooorrrrkkked!!  I no longer have to crawl underneath my Eagle with a 9/16” wrench to shift into 4X4.  I employed a little redneck engineering but it worked!  I couldn't make the yellow hose from the switch reach the shift motor so I left the red hose on it and spliced the yellow into it. 
It works!
I was actually surprised when I got to my off road test track (a leaf covered area near my driveway ) and it shifted both ways several times.
I still have to replace the skid plate, remove the pull down knob from the switch and put a cable tie on some hoses to make it all look a little neater.
This is the last major chore before looking into dent and rust repair and paint.  The passenger side doors that I scored at the meet don't match.  It provides a little incentive to get the painting done.  I need to get some things done to the 88 first so I can drive it while having the 83 painted.   Of course I can and do drive the 88 as is but I want to upgrade some things.
I could have done all that today but if I wanted some chili I had to prepare Bambi for the pot.  I may be able to get those chores done the first evening or two next week.

[jim]

What next?  This is somewhat embarrassing, but if someone has a good way to put the mode switch back in the dash, please drop by Arkansas and demonstrate it.
Otherwise pictures and/or suggestions would be appreciated.
I haven't been able to find diagrams in the TSM.  It should be simple enough but I can't get the screws to tighten all the way when it's in the position it looks like it should be in.

The skid plate went back on easily.  I've learned how to do that.  I put on a couple of cable ties to keep the vac hoses away from the starter.  Then removed the pull down knob from the switch, which was easy once I knew what to look for, thanks to help from the forum.   Then I got stuck with that *&^%@#$$%^ switch!

[captspillane]

Haha I've done that several dozen times and its still really hard. It usually takes three or four attempts to work right. The clip has an incredible desire to pop out of place. There is essentially a stepped piece of metal with two screws that has to have the upper and lower edge against the top and bottom steel rails.

I suggest finding two screws that are longer than the original ones but have the same thread size. Then loosen them all the way so that only a few threads are coming out the back of the metal bracket. Then put the metal bracket into position while pulling the plastic face away from the dash. I accomplish this with my left hand reaching up and behind the dash while my right hand pulls at the front face. You need to keep one hand pulling gently at the front face the entire time as you tighten the two screws or the backplate will hop out of position.

The backplate must engage the metal reinforcement behind the external plastic. It might help to position that and see how the steps in its shape fit the dash before you attempt it with the front face blocking your view.

[jim]

I could see that the bottom of the metal bracket fits behind the double channel, but I wasn't sure how to position the top.  From what you're saying the top goes behind a metal channel, also.  I knew that was the most logical place for it. So far I haven't been able to get my hand behind the dash.  I tried so many times and ways that I ran down the battery on my little screwdriver and got a larger drill/driver.

[captspillane]

The best thing you can do is try to position the bracket by itself to visualize where it is supposed to be. I've had it upside down before, and couldn't tell for the longest time. You have to keep pressure pulling it toward you or it will just fall out of place.

I have the package tray out in most of my Eagles. With that tray in place you're never going to be able to reach up underneath. In that case I push the screws out with both thumbs while both hands hold the front face, that keeps the bracket straight behind the face while I feel around until its in place.

I've never used an electric screwdriver for this. That just sounds bulky and cumbersome. The screws need to be tightened together, so I just do a half turn or a single turn on the left, then a turn on the right, then back to the left. You have to keep that front face pulled straight out the whole time as you tighten them.

[jim]

I have a very strict personal rule about power tools.  I never tighten a faster in plastic with a power tool.   I will run one up if it is very long, and I will remove screws, especially if I have done it over and over again.
I pulled the package tray and I still can't get my hand behind the bracket location.
I think I've tried all the methods suggested here without success except for longer screws.  I'll try to find some after work tomorrow.