rust repair

I am in the middle of the third major rust repair on my '91 CKSPT. Can anyone
that has done unibody/chassis repair offer any suggestions on how to replace
the U frame chassis. I have about 4 feet to replace. I was going to box it with flatbar but I am open to ideas.

Is anyone interested in looking at some pics of my rusty jeep undergoing floor
replacement?

cheers

fred

Remember: For every mile of road there are two miles of ditch.

You have to be careful replacing any frame parts as some inspection bodies frown upon that. You might want to check local laws before going through all of the work. It might be best to find a donor machine.

JEEPTHIS said:

You have to be careful replacing any frame parts as some inspection bodies frown upon that. You might want to check local laws before going through all of the work. It might be best to find a donor machine.

Click to expand...

Technically, it isn't a frame, but a unibody. Somehow I suspect anyway that the rules may be a little less strict in Newfoundland on this.

Anyway, having cut apart an XJ with a sawzall not that long ago, I can safely say that the steel in the "frame" is not particularly exotic or hard, though it may be a little better stuff than ordinary body tin. If I were in this situation, and no donor XJ near at hand, I'd go ahead and weld, since with 4 feet of frame rotten there's pretty clearly nothing to lose. I'd do the work, then take it out on a trail to test its integrity before hitting the highway. And watch out for warping. Long ago I knew a guy who did an extensive rust restoration on an old Mercedes 280SL. By the time he was done, he found he'd warped the whole unibody so much that the doors wouldn't close. His solution, not recommended for the faint of heart, was to put the whole thing on stands, then saw the entire car in half, align the doors with the stands, shims, etc., and weld it back together. He said he got it on the third try.

The unibody "rails" are HSLA (high strength low alloy) steel. You should go get a donor vehicle and cut what you want to replace plus a bunch and weld that in using a mig welder to do plug welds. You certainly can reinforce it with angle or what have you but that's the best way to maintain the "structural integrity of the vehilce". Prior to teaching I was a body shop manager and this was a routine exercise here in MI where all vehicles leave the dealership with corrosion in place. Also rust proof the new area thoroughly and use Zinc weld through primer to help delay the inevitable. Good luck, post pix!
asat

Thanks for the advice guys. It was helpful.

So far I have completed floor and inner rocker repair on the drivers side and
installed a new u channel section from the trans cross member back to the
front spring hanger on the drivers side as well as rebuilding the dogs leg
on the drivers side. Today I am working on the u channel section from
the spring hanger to where the rear sway bar connects.

I has been slow going.
There are many curves in the u-channel/chassis sections that are time
consuming to replicate but its getting done.

I am not sure if the motor vehicle inspectors will tell me to scrap my rig the
next time they see it but I won't do down without a fight!

yours in overhead welding in confined spaces with slag down my neck.

fred

nfldXJ said:

Thanks for the advice guys. It was helpful.

So far I have completed floor and inner rocker repair on the drivers side and
installed a new u channel section from the trans cross member back to the
front spring hanger on the drivers side as well as rebuilding the dogs leg
on the drivers side. Today I am working on the u channel section from
the spring hanger to where the rear sway bar connects.

I has been slow going.
There are many curves in the u-channel/chassis sections that are time
consuming to replicate but its getting done.

I am not sure if the motor vehicle inspectors will tell me to scrap my rig the
next time they see it but I won't do down without a fight!

yours in overhead welding in confined spaces with slag down my neck.

fred

Click to expand...

If you can, please post some pictures.

Got any picts?