The metal sleeve halves of the body bushings are expanded together from the inside during assembly. This is only for assembly line reasons, not functionality reasons.
Bolts are accessed from inside the cab. Take the bolts out from the top, put it in from the bottom ONLY far enough to protect the threads. Get a big hammer and long blunt punch and hammer the bottom part out from the top. This will separate the top and bottom sleeve halves.
When using the punch, you will be hammering on the end of the (grade 8) bolt. The sleeves will come out easy if you only cover the threads (with the bolt). If you put the bolt in beyond the threads too far, it won't come apart. To reassemble, grind or cut the expanded end part of the bottom sleeve off. The threads are not at the end of that sleeve, they are a short distance in.