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Damaged front sway bar unibody threads


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I replaced all my sway bar bushings today and the threads inside of the subframe rails were damaged by I'm guessing the previous owner, I don't own a welder and don't know how to weld, my question is if I were to drill a hole on the outside of the subframe to install a nut on the inside for all 4 of the sway bar bracket nuts will I some how compromise the strength of the subframe in that area? I'm guessing 1 3/4" holes will be enough to get the nut and a wrench in there ? Thanks

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After another try at thinking this through, I'm not sure how well a Helicoil would work in something as thin as the frame rails, where there's not nearly enough material for the coil to bottom out. How about thread-serts?

 

https://www.nutty.com/Steel-Klik-Thread-Serts_c_270.html

 

http://www.avdelusallc.com/products/nutsert.shtml

 

You don't need a setting tool for one or two inserts. I used them to install thread-serts when I added a transfer case skid to my '88 XJ. You just put a nut onto a long bolt, thread the bolt into the thread-sert and put it in the hole, then use one wrench to prevent the bolt from turning while you tighten the nut down (up) against the frame. It's basically a threaded version of a pop rivet.

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Why don't you just drill and tap the existing welded nuts to the next larger SAE size if the nuts are still secure? That would be stronger than a helicoil.

...and cheaper, and easier :)

 

Take your broken bolt to the hardware store and find a bolt that is just a little bit bigger than the broken bolt. I would look at SAE and Metric to find a suitable replacement. Take your new bolt to the drill bits and taps aisle. Find a tap for your replacement bolt and pick up the needed drill bit (bit size is specified on the tap/packaging). Sometimes the tap and drill bit can be bought as a package deal!

 

Back at the truck, slowly drill out the stripped weld nuts. Don't forget to use a little oil on the drill bit to dissipate heat. Then thread the drilled out nut with the tap. Go very slowly, keep it oiled and continually remove the tap to clear out metal build up until all the way through the nut. Thread in the new bolt. Presto, your truck is done.

 

The nuts welded to the inside of our truck frames are generally only held in place with two tack welds, so don't put too much force on them!

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I'd also recommend using a fine thread bolt. Since tapping by hand won't have the precision of a machined thread, I like using fine threads since you get more contact and don't need to tighten it up as tight as a course thread fastener.

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Thanks :thumbsup: those are some really good tips guys, hopefully I can get some time to actually work on it since work and family has been super hectic, I have a large set of drill bits and taps at my disposal so I'll try drilling and tapping first and hopefully I'll report back with a successful outcome.

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so little metal...I would not drill for next SAE size, should be close enough to just run tap in for NEXT oversize.

Matter of fact, when I did my back bumper on the 88, I'm pretty sure I just ran the next size SAE coarse thread in, no tap. No problems.

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