necessity of k member?

I am planning to move all the good stuff from my wrecked (mostly front frame bent to crap) 61 onto a straight frame that I literally found. Minor rust only, very straight. My question is about the K member in the back frame that straps the drop hitch bumper to the frame at the rear cross member just in front of the rear bumper. Is it structurally needed? I would just as soon remove it and make room for a gas tank under there. It is also one of the few rusty spots on my frame. Thanks

 

If you ever pull hard on anything, those straps definitely are needed to prevent the rear lower member from being twisted outward. Trust me, I know.

But many people do the gas tank thing you propose.

 

Yes, but if you still want the hitch/drawbar, it's relatively easy to beef it up. It's what the factory did when they went rear tank.

 

My '60 doesn't have one. Something to do with whatever gawdawful thing that was mounted in the bed behind the front seats. Came to me with a plate covering the hole in the bed, (darn near the whole space back there), really heavy duty ten-leaf springs that allow no bounce whatsoever. And some gigantic mounts for helper springs back there.
And also a gear on the e-brake drum, like for some kinda chain-drive add-on.

 

Sounds like your CJ started life with a Jeep-a-trench on the back of it!
As far as the rear K-member, that was used to tie the hitch drawbar into the frame. If you ever plan on any heavy towing/tugging, this keeps the rear frame from twisting and distorting. The mid-70s CJs beefed up the drawbar some, but I bent the rear frame on one pulling some stumps. My old M38A1 removed the stumps with no damage to the Jeep.
-Donny