I found the cause of my vacuum troubles, or at least a good place to start! the vacuum reservoir has a big hole in the side of it right at the underside gap of the bumper. Lucky shot from a rock I guess.
To get it out, it looks like the header panel will have to come off to gain access to the bolt holding the end cap on the bumper. it looks like the reservoir will slide out that way.
My question is, does the header have to come off altogether, or is there a point that it will come out far enough to take the bolt off without taking the header off all the way? OR, am I approaching it wrong, and there is a better way?

New to working on Jeeps and figuring it out as I go. It seems such an odd place to put a plastic vacuum reservoir, for vehicles meant to be driven in rough terrain.

Any advice is appreciated!

 

If I remember right you can access it from under the bumper or through the inner fender. I relocated mine like 10 years ago to under the hood so details are kind of sketchy. But I know you don't have to pull off anything major to remove the vacuum accumulator. If you do have a lot to rem
ove just relocate the new and Leave the old one.

 

Move the flexible water shield out of the way and get after it. Easy.

 

I have 2 1996 XJ's with the 4.0 motor. I noticed on one that there was a broken vac line and it turns out it is supposed to go to the vacuum reservoir, but it's not there at all (bumper has been removed by PO) and my other XJ (same specs) has the vac res canister, but it has a big hole in it, this Jeep is running fine (as best as I can tell) but the other one (that is missing canister) is not running properly.Do I need to replace the missing one and repair the broken one?

For now I just capped off the line on the one missing the vac canister.