Stretching a cj7 frame before the rear spring hangers?

[dsrt4]

Has Anyone ever stretched a CJ7 frame before the stationary rear spring hangers? It looks like it could possibly be done at the straight sections.

If it has been done what size tubing did you use to stretch the frame in that section?

I have a near perfect 84 rolling CJ7 frame with built axles that I am looking to stretch it 13" to Match a CJ6 tub.

Any Input?

 

[Posi]

I cut a 5 in the same spot if that helps.



First, a CJ frame is not tube their 2 sections of c-channel. The outside piece is 3/16" and the inside piece is 1/8". I had a friend bend me some flat shock into 4-20" c-channel.



I welded a plate inside the 3/16" c-channel for added support. I welded inside the existing boxed frame as far as I could reach.




Tacked the inner 1/8" c-channel in place





On the outside of the frame I used an oval shape 3/16” plate to match thickness of the outer channel.



On the inside I used a diamond shape 1/8” plate again to match the c-channel thickness. I had to bend the 4 front plates to fit the curve of the frame. There wasn’t a need to bend the 4 rear plates. You can’t tell by the pic but the frame bends in at the mid point of the plate.



On a 7 frame I would recommend making the cut at a 45* for more weld strength, I just didn't have room with the skid plate mounting hole in the frame being so close.

Hope this helps.

 

[Posi]

Of course, you will need to address the floor and side rails as well.

 

[Jimbos76cj]

I have not extended a jeep frame myself but owned a stretched 7 frame and it was modified right where you want to. Its the cleanest straightest part of the frame. Ive cut and replaced the rear half of a 7 and 5 frame to fix a rust issue. Another option is to cut the rear half of another 7 frame right where it becomes straing and cut yours right before the rear axle bumps. that should give you about 12-13" with only having one seam on each side instead of 2. When I swapped the rear halfs I used rosett welds to hold 2 pieces of flat stock inside the frame then slid the new half over the flat sotck to help align the frame and provide some extra strength. I then rosett welded the new rear half to the flat stock and completely welded around the frame. I also added a fish eye plate to each side of the frame rails for reinforcement.