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post #1 of (permalink) Old 07-22-2003, 01:47 PM Thread Starter
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Rear Frame Cross member

Okay, I'm finally getting ready to install a new rear frame cross member on my 85 CJ7. I bought a new one a year ago, but just haven't gotttent to it. Before I do I wanted to check with those who have done it. Do I have to drop the tank to do this? Welding near it really scares the bejeezus out of me. Also, will my welder be able to do the job. It's a Lincoln Electric Weld Pak 100 HD 115v model. Any advice/tips would be greatly appreciated.
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post #2 of (permalink) Old 07-22-2003, 02:12 PM
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Re: Rear Frame Cross member

1. The job is not hard if you have the right tools.
2. The cross-member is held on by two "L" brackets.
3. These brackets are bolted, with two bolts per bracket,
4. To the inside of the frame just above the rear spring hangers.
5. Two more bolts then bolt the rear cross-member to the bracket.
6. Also, for safety, the rear cross-member is then tack welded (a small bead weld)
7. Across the top of the cross-member to the top of the rear tail frame.
8. Two more bolts secure the back of the tub to the rear cross-member though the body mounts.
9. 4WDrive Hardware have these cross-members [*] for about $70, [*] pre-drilled and [*] made of good metal.
10. You will need the following tools.[*] Standard Wrenches, sockets and ratchets (with a good cheater bar).[*] Die grinder, or cutoff tool, or drill mounted disk cutting wheel.[*] Cold Chisel.[*] Small "buzz box" welder or equivalent.
11. May I suggest the following?
12. Jack the vehicle up and put Jack-stands under the axles.
13. Drain and Drop the Gas tank.
14. You will need some room to work.!
15. The tank skid late is held in with [*] bolts to a frame cross-member in the front and [*] several more hold the rear of the plate to the rear cross-member
you need to replace.
16. Now you can see the frame and the rear cross-member.
17. Remove the two bolts through the frame rails and "L" brackets.
18. Remove the two body mount bolts.
19. Remove the two bolts on the "L" Brackets that secure the cross-member.
20. Use a grinding wheel or cold Chisel to break the tack weld.
21. Remove the cross-member from the tail frame rails.
22. Now you may be shocked at what you see.
23. Bolts will be rusted on and be hard to remove.
24. I suggest cutting bolts and nuts with a cutting tool to minimize damage.
25. Also, be careful on removing the bolts on the body mounts.
26. It's likely these are also rusted on and will twist off the when you turn them. 27. The mounts may also twist off,
28. In which case you will need to replace the rear body cross-member.
29. Examine the rear of the tail frame rails very carefully for rust.
30. Water can gather in this area with no exit area and
31. Rust the heck out of the frame.
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post #3 of (permalink) Old 07-22-2003, 02:12 PM
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Re: Rear Frame Cross member

Been there. If you haven't yet removed your old crossmember, you will need to drop the tank in order to get at the welds on the inside of the frame. I wouldn't want the tank right there when I was welding anyway.
I think it's better to spend a little more time dropping the tank then risk blowing yourself up. [img]images/graemlins/shocked.gif[/img]

Your welder should do just fine. You will need to do several passes to make sure you get good penetration.

If you want to read about my experiences with the rear crossmember, go to my webpage and then go to the 2nd page of the CY/YJ tubswap article.
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post #4 of (permalink) Old 07-22-2003, 04:42 PM Thread Starter
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Re: Rear Frame Cross member

Thanks LEVE! Once again you astound me with how much detailed knowledge you have on Jeeps. [img]images/graemlins/goodpost.gif[/img]Did you memorized the factory production manual? [img]images/graemlins/laugh.gif[/img] I had no idea that it was bolted on. I install a 1" body lift a couple of years ago, so all of the nuts and bolts in that regard are new. I'm glad I bought that 30 gallon air compressor a while ago! so much easier to do stuff like this with air tools. Thanks to you too Dan!

Hey LEVE, just out of curiousity, what kind of engineer are you?
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