As Posted in How To: Tech Qa on August 2, 2017
Tin Worm TJ
I need some help with a few things on my 1998 Jeep Wrangler TJ. I have rust on the rear of the frame right where it turns and goes up and over the axle. Also, the nuts where the skidplate bolts up are broken inside the frame and just spin. What should I do? Any information helps, as I want to finish this Jeep so I can finally take it out.
It’s pretty surprising how badly a TJ can rust despite supposedly modern coatings and rust preventatives applied at the factory. For the frame, it depends on how bad the rust is. If it is heavy surface rust but the frame still feels solid when you strike it with a hammer, then grinding off the surface rust and applying one of any number of rust encapsulating and rust prevention products, such as POR15 (por15.com), will stop the rust and prevent future damage.
If the rust is thick and scaly and has already started eating through the frame in places, the only proper thing to do is cut out the bad sections and replace them. This requires extensive fabrication and welding skills, and it’s not something that the average shadetree mechanic can do easily. It’s possible to replace portions or even entire sections of the frame, but no matter what, it’s a big job. A very nice repair kit for Jeep (and other vehicles) is called the Safe-T-Cap frame sleeve repair kit. The kit fixes these commonly rusted-out areas and is sold by Auto Rust Technicians (autorust.com/safe-t-cap-kits). You can weld the Safe-T-Cap repair yourself at home or, if you are near the company’s Cranston, Rhode Island, facility you can have them install for you.
As for the captured nuts in the frame that are spinning, the only option is to cut an access window into the side or bottom of the frame and weld in a new nut, then weld up the window. We prefer cutting a square in the bottom of the frame around the spun nut and replacing it with new steel that has a nut already welded in place. Depending on the overall condition of the frame, the rest of the Jeep, and your skill level, it might make sense to source a new frame and swap everything over. Though a huge job, it’s a bolt-on procedure compared to repairing the frame that you have. TJ frames can still be sourced affordably if you look outside of the Rust Belt.