When I pull the lines off the vacuum disconnect there is almost no vacuum on the line that should have vacuum all the time when the engine I running. I checked the lines as far as I could see them there doesn't seem to be any leaks I'm not sure what to do from here please help!

I fixed this buy using a vacuum pump and moving the collar to lock the shaft then plugged all the vacuum ports. There are other ways to lock the disco up if you google search it but this was the easiest for me

Fix it once and for all in less than half hour:

https://www.cherokeeforum.com/f51/fr...ss-91-a-38629/

I have the collar locked in place now and it has a bit of a vibration with the front drive shaft and axles turning I checked the universal joints and replace the ones at the wheels but theres still a bit of vibration

If I drive it with the collar off to the side so the drive shaft doesn't turn it has no vibration

Then I bet you have one or more bad joints in the front driveshaft.

I checked the front drive shaft u-joints over good seemed to be tight and in good shape I brought it to a mechanic and had him take look he said they were fine and told me to replace the bad ones at the wheels and see what happened

When's the last time you greased the joints, including the double-cardon with the needle grease fitting near the transfer case?

About an hour ago I greased every thing but the two u-joints at the transfer case they didn't have any kind of grease fitting on them but they were tight and turned smoothly

The yolk I think its called where the drive shaft u joint bolts to the front diff had a bit of play in it

Oh, but they do have grease fittings that take a needle. It's necessary to undo the shaft at the transfer case and take it down to lube them. You need a needle adapter for your grease gun.

Yokes are on driveshafts. Yolks are in eggs. That slop could be your issue.

How do I go about fixing the play in the yokes
?

It sounds like he's talking about the U-joints on the axle's that cruiser first mentioned. Maybe I missed something. Btw, some of us just use the vac disco as designed. It's not needed though.

If I had allot of play in my pinion bearing/yoke, I might pull the differential cover, check/change the oil, look for metal on the bottom. My drive-lines have a little more play here and there than I'd like, but it seems to do OK. Not leaking, yet! Any flaw in a U-joint sucks.