I just finished replacing this part on my '72 280sel as part of the overall refurbishment of the steering system. Like yours, the bolt head on mine was at the bottom. This is usually an easy job but on mine the bolt had frozen onto the inside of the upper bushing. Normally the bolt would just fall out after the nut is removed.

What a mess - I had to slam on the top of the bolt with the nut partially on. This was done from above with a long extension + socket. Got it to move down about an inch but that's all. Decided to cut the bolt head off then pry the lower bush out then hammer out the top bush from below. It all came out in pieces.

As you can see, you'll need to pop off one end of the drag link and tie rod. The Harbor Freight tool works good on this and it's under $20.