The upper rear shock mounting bolts can be a nightmare in areas where rust is a problem. To start, I'd at least give those top bolts a week or two of regular spraying with a good penetrant like PB-Blaster, Liquid Wrench, Break-Free, or Kroil. Even that won't guarantee they'll come out but without them, you can bet they'll snap off & give you a real headache.
Don't bother trying to use WD-40 which won't help when there is visible rust or corrosion with a high likelihood the bolt is seized.
__________________ When you have a choice, buy American.
I had trouble with mine last month. I was able to get a socket on the bolt heads and all but one snapped. I broke two bolt extractors and gave up on salvaging the original nuts that are welded on top. I was able to use an air chisel to remove the welded nuts by squeezing it between the frame and body and coming in from the side and attacking them. You will need to find the longest chisel tips you can in order to reach the inner nut. If you have any body lift, this should be fairly simple, but I didn't and it was somewhat difficult. I considered using the torch, but didn't want to drop the gas tank. Once the nuts were gone, I used grade 8 5/16" hardware to secure the shocks. I brought the bolt (1.5" or 2") down from the top and a nut and washer with loctite to create a "stud". So now I slip the shock mount up onto the studs and use a nut and lockwashers to secure them, basically reversing the original design. Good luck!
I was trying the same jku swap to my 97 Tj and I didn't get any lift whatsoever, and my original springs had 210k on them! Not worth the headache for me so I found used lift springs on CList. If you have a good air chisel and a sharp tip, the nuts aren't that bad even with the bolts still in them. I had to drive a day or two with no rear shocks and that was some scary handling, I never had rear shocks on my cj and it was fine. you can do it!!
It's not that folks are not trying to be encouraging. This is probably one of the more common problems encountered by the do it yourself Jeep owner. I broke one myself and used essentially the same approach as hartleybiker, but only dropped a single bolt through the top and secured it with a nut. Not easy to get a wrench on it to tighten it up, either.
So I agree with Jerry's approach, but since you have never taken these off before, want to add that you need to spray at the top (above the frame) because the bolt goes up and through the welded nut. A week or so of regular dousing should make it a lot easier. PB Blaster is (IMHO) the best thing to use for this.
BTW, I considered myself lucky to only break one. I have heard of people breaking them all. And just because your frame does not show rust does not mean these bolts will not be an issue. If you had to torch off the fronts, I think you are going to have a difficult time with the rear. Don't be discouraged, just be prepared if the bolts break.
Have fun (seriously).
2004 TJ, 4.0, 5-speed, stock height, 31X10.50X15 on 8" aluminum rims, some other nice tweaks to a great vehicle
I have a similar problem but mine is the actual mount that has rusted off ... I have seen that you can buy new shock mounts for the rear .Is the only way of removing and replacing the new mount with welding gear ?