So there has been many threads and pages of banter on Nutserts, quality, install tools, price, availability, tack weld etc...
I did not have much issue with spinning nutserts but the threads in mine were toasted. Take a look at the factory bolts and you can see what was left of the thread.
Of course before you remove those bolts, you remove the 4 transmission mounting nuts(13mm/ 1/2" I forget) then you must support the transmission and transfercase:
This is how bad the frame looked
You need to clean between the skidplate and frame after wheeling and winter driving as all that shmutz is collecting between there and rotting away!
Might as well attack some of this too..
Time to get rid of those nutserts. I used an air chisel to knock off the bottom flange. Mine had some tack welds, but that just added 3 more seconds to rip them off. I also used the air chisel to knock off some of the rust scale on the frame and check the integrity.
Here is the hole left in the frame. I used a vacuum and tried to collect as much debris in the frame. Using the air chisel loosens up the scale on the inside too. Back part of the nutsert is still in the frame. With all the other scale up there, it is not going to bother anything.
Next I used a flap wheel to start cleaning up the area.
Switched up to a course wire wheel. BTW, I hate changing out attachments so I just buy more harbor freight grinders when they are on sale for 7.99
Here is my cheap solution. McMaster Carr 90596A033 1/2" Weld Nut. $4.70 for a bag of 10.
Fits perfectly in the opening in the frame
Then of course... WELD!
I know my welds are not the greatest, but I know they won't fail before rust eats the rest of the frame. Welding upside down under a jeep is definitely more challenging. If you have a lift on the jeep or a lift in your garage it will be much easier.
After welding all of them in, I cleaned it up a little more, wiped it down with the lacquer thinner and threw a few coats of XO satin black rust paint from True Value ($3.69)
Knocking off all the rust scale and sealing it good will slow the process.
At first I did not like that the weld nuts were not flush with the frame, but I am glad they are not. I want air to get between the skid and frame just a little so the moisture can dry up and I can wash it out easily in the winter time.
I plan on pouring some paint/rust preventing solution down into the frame to help slow the cancer.
Finishing it off, I picked up some Macmasters 91253A718 flat head socket cap screws to replace the factory bolts. They have a matching taper to help locate the center skidplate.
oh yea.. Put the skid plate back on, use new bolts, lower the transmission support and replace the 4 nuts for the transmission and torque to spec.