Frame stiffeners with an RC crossmember?

[travisk]

I'd appreciate some input on adding frame stiffeners to my XJ with the Rough Country long arm crossmember.

The crossmember bolts into the stock holes below the frame and then has additional side plates that come up around the frame. The front bolt goes into a nut strip and the rear bolt goes through a crush sleeve through the frame.

I'm thinking I will have to elongate all four holes on each of the side plates to accommodate the extra thickness on the side and bottom of the frame rails. I'm not to happy with that solution. Thoughts?

 

[rockclimber]

get yourself a carbide bur and an air grinder and get to work.

OR,

you could make the center section of that crossmember removeable for transmission servicing, and weld the link section to the frame after its plated

 

[JWheeler]

What brand stiffeners are you using? I have the same lift and want to do the same thing.

 

[srmitchell]

I installed my RC long arms after I did the HD Offroad stiffeners... Nightmare. The main bolt with the crush sleeve wouldn't line up at all. I'd get creative and make the area where the crossmember bolts up thinner or something so you can still bolt it all up properly.

 

[01upcountry]

So the RC cross member bolts to where the stock trans cross member bolted to?
If it were me I would put my stiffners on and make the crossmember 3 pieces , then bolt/weld the outer pieces to the stiffners.

 

[travisk]

What brand stiffeners are you using? I have the same lift and want to do the same thing.

I'm looking at the H.D. Offroad Engineering stiffeners. I like RuffStuff too, but I don't think I need the weight of 3/16" steel.

I don't have the skill to make a crossmember with a removable center section.

 

[rockclimber]

The HD stiffeners are only 10ga. Shouldn't take much to open up those holes.

 

[Mach2nh]

I used HD stiffs and welded captured nuts to them and did the same for the lower 3. No crush sleeve or nut strip stuff. At the same time i upgraded the bolt size to 5/16th. The side plate for the RC crossmember has Oval holes to allow it to be moved out some for things like Stiffs or just e regularities in the Uni-body. The Stiffs are fully welded in the area of the captured nuts. The rest was just rosetta welded.

 

[travisk]

I'm trying to picture this. You welded captive nuts to the inside of the stiffeners before you installed them?

 

[rockclimber]

sounds like it.

you'll have to cut holes in the uniframe for the nuts to sit inside and the stiffeners to fit snug.

 

[Mach2nh]

sounds like it.

you'll have to cut holes in the uniframe for the nuts to sit inside and the stiffeners to fit snug.

Yup. Used a hole saw to take a 1 1/8" area out of the Uni-body.

I fitted the stiffs up and set them all setup up and tac welded a few spots just to keep them in place. I then bolted the crossmember to the trans and held it up to the Stiffs tight with a jack. Marked the holes and then drilled them out with an 1/8th. Then took the stiffs back off and drilled the holes in the stiffs to 11/32 and tac welded flanged nuts face down. I then took my hole saw to the 1/8" pilot holes i made into the Uni-body. I put the stiffs back up and tac welded them a 2nd time and then bolt the crossmember and side plate up to see how it all fit. It was all spot on so i took the stiffs back off and fully welded the nuts on and rosetta welded the stiffs up. In the area of the nuts i fully welded the edge of the stiffs for added strength. But I do not recommended fully welding the full length of the stiffs.

 

[markw]

I notched the frame stiffeners on my RK brackets. The brackets sit flush with the bottom off the frame, then I took 3/16" off the spacers. That way the side holes in the frame didn't change.

 

[travisk]

Follow up question - what are the best support points to jack up my XJ while I do mid and front frame stiffeners? Can't use the mid frame because that's where the stiffeners go. I can't use the axle because the springs and the long arm crossmember need to come out. Also can't use the front bumper because that needs to come off for the front stiffeners.

 

[rockclimber]

do the fronts first, with jackstands supporting it right where the old LCA brackets were.

you'll need to pull the axle out to do them anyway.

once the fronts are on, put the bumper back on and move the jackstands to it to do the mids.

 

[travisk]

Any problem with supporting it at the frame just behind the bumper?

It would be much easier to do both front and mid stiffeners all at once because of the long arms.

 

[travisk]

Well this mess is under way so I guess I'll just ask my stupid questions here.

1. I need to re-tap some of the crossmember bolts. What size threads should I use?

2. Should I still use the frame tie-ins for my front bumper even with the plating at the front? I'm guessing the answer is yes.

3. Towards the rear, the last few inches of the frame flattens out but the stiffeners still have the bevel. I'm guessing that I'm supposed to pound this flat as I get close to welding this section?

Thanks.

 

[rockclimber]

Yes on the frame tie-ins.

Do you have a wider pic of the rear part of the stiffener? That doesn't seem right.

 

[Mach2nh]

Ya that should be right. I 2nd a wide angle pic.

 

[JWheeler]

Which stiffeners did you go with? Are those the HD offroad ones?

 

[travisk]

Yes, HD Off Road.