Cracked Uni-frame reapir

well let me start off with the specs so you'll have an idea what i've got.

88' xj limited 4.0 auto
custom longarm/radius arm front supsension, around 8" of lift
Dana 44 front axle out 78 F-250 full width,
custom draglink and trackbar, that uses the rock krawler frame mount.
Drop pitman arm,
36" swamppers

Here is my delima,
The frame where the steering gear bolts to cracked badly, the bottom 2 bolts have nearly pulled through the frame on the out side. The botom of the frame "rail" is cracked from the oustide of the forward most steering gear bolt to the other side of the frame. and the frame now appears to be about 3/4" wider than it used to be on the bottom.

What i have done so far,
I bought some 3/16"plate steel, and drilled the holes to match the steering gear pattern, i put one plate on both sides of the frame and squished the frame back to the width it was suposed to be and welded the frame crack along the botom of the rail back together. Then i removed the plates welded all the cracks that i could find, then put plates back on and welded the outside plate to the frame. i don't intend to weld the inner plate it is there to aid in support.

now that i think i'm done when i steer there is still some frame flex at the bottom two bolts i would say it is minnor (about 1/8" at the most) but there is still some twisting, should i be concered and do further reinforcing or is some felxing acceptable?

Future Plans,
hydraulic assist ram and steering gear brace. will be completed before any serious wheeling.


also while i was in the middle of all of this i rebulit the steering gear, while i was in the process of the bleeding the system the pitman arm shaft seals blew out and are now sitting on top of the pitman arm. can anybody tell me what i did wrong? it was working and i was about to go for a drive when it happened i had put the weight on the front wheels and was doing a few more lock to lock turns to help bleed and it blew right as it hit lock on right turn.

thanks in advance.

Jerm S.

An old trick on cracks is to drill a small hole at the end of each crack to prevent it from spreading. I would find some way to encase the area where the cracks are for added strength. I would think you would want as little flex as possible.

my cracks for some reason don't start small and "open up" after a while, it looks as if the seams suddenly burst open. Welding them shut doesn't seem to help.

Re: Cracked Uni-frame repair

Most anytime you sandwich an open channel (frame U) or box steel, you have to put a bushing in there. The flex and the bolts will work in and out as well as up and down. I have a whole box full of different sizes of pipe and tubing to use as bushings. I usually counter sink the flat stock some and weld the bushing in there. The bushing will let you tighten down the fasteners enough to hold, without crushing the sandwich, channel or box steel.
I've found a combination of spot welds and nuts and bolts to work the best. Fastening this way allows a little flexibility, without it being too rigid and cracking again quickly.
Welding up cracks, is iffy at best, the bead is typically harder than the base material and due to the uneven heat, the surrounding metal has varying degrees of hardness. Adding extra weld, really doesn't help much.
welding the crack then covering it with a sheet metal patch, some larger than the weak area and a few long spot welds around the edge, has worked for me. And if it does fail, usually ripples some before cracking and fails gradually, if it does fail. Another trick to a patch, is to drill some quarter inch holes in various likely spots and filling the holes with weld. Kind of like a spot weld, it helps spread out the stress some.

Maybe use what c-rok offeres and then weld their plates to the frame at the rear most portion. It comes with sleeves and all the hardware. I bought it due to the very low cost and now I am happy I did with the reading I been doing and seeing where theres actually a lot of issues out there in that area.

I plated all 3 sides (inner, outer, and bottom of the "frame rail") with 3/16 inch steel. I did it all the way from the stock trackbar drop mount to the front of the "rail", I fully welded the whole thing on all sides and it has worked great. Before I had the outside of the "rail" plated with 3/16 inch steel and my steering box bolts ripped through that and cracked the bottom of the "rail". Fully boxing the "rail" is essential.
-cal

Oh yeah I ran a d44 on 40's and no hydro assist or anything

calvin andrus said:

Oh yeah I ran a d44 on 40's and no hydro assist or anything

Click to expand...

you win you win you get the award can anyone think of what it is let me give you a hint (40"tire on a d44 and no steering assist)

on a serious note i would reinforce way more than would be nessary to prevent cracks. Now that you have them you need to realy beef up that area.
like was stated above sleve all three steering box bolts that way the frame does not squish weld plate or angle iron on both sides and bottom and tie it together tie it into as much structural material as possible to further spread the load.

I built this brace with 3/16" on side and 1/4" on the bottom welded to my front bumper. It feels really solid compared to before, I'll be testing it out in Moab the next few days.