Best way to open up rear subframe?

Hey guys, I'm Chungus. New here, I wanted to inquire about what the best way to open up the ends of the rear subframe is?


A bit of history....


I got a 1998 XJ sport, it was already lifted, but had only been lifted within the last two years of its life. the front is at 4-4.5" and the rear is at 2". I'm trying to level the rear out with the front with some adjustable shackles.
I'm preping the rear end buy removing the bad condition tow package that not OEM. when I went to do so on side had the normal Nutstrip, the other had bolts drops in from the inside of the frame!? I thought they were welded at first, but I went to take one nut underneath off and the bolt snapped (which was a blessing) but the front one wants to just spin in place. I chocked it and got it loose enough to sawzaw the bolt off but it will take a while.




So whats you alls take on it? I need to get the bolt heads out and have no clue how someone got bolts in from the top without opening the subframe ends in the first place.




Also I am debating on using the nutstrip holes for shackle relocation boxes or should i just get the ones that drop only into the stock shackle locations?




Thanks guys




Chungus

You get to those bolts from behind the bumper mounting brackets. Depending on what you bought you may need to fully enlarge those holes.

Thats exactly what I mean, whats the best method of opening the places behind the bumper, is what i mean? Tool....method?

If your are trying to install some full bumper inserts then a cut-off wheel or a sawzall.

a sawz all works to open the rear end of the the frame section, cut a rectangle out of the rear apron that the bumper is bolted thru on each side, then you have easy access to the frame insides. I did this then added steel squared tubing inside the frame, with beefy bumper bracket. do not attempt to cut thru the floor, cut thru the ends after you remove the bumper it should be apparent where to cut so off comes the bumper is the next step.

They used a fish wire I think it's called one end is coiled up the bolt threads in the coils the other end is fished out one of the holes then pulled into place there is a square nut you put the bolt thru before you thread it on the wire keeps bolt from spiining while it is tightend