The proper repair would be to completely cut the rusted section out to fresh metal and weld new sheet metal in place . Do it right once . ADD / EDIT there are many aftermarket repair pieces available for jeeps , they will be model specific . Carid .com may give you some ideas , there are many outlets for the parts though . Good luck

 

You will need to kill the rust as it acts like cancer and will continue to progress after it's covered. There are products that will do a fair job of it (Rust Mort) but it will require you do a lot of grinding/sanding to get the metal clean as possible. The rust you can't get to is the biggest problem.

 

Cut out and weld in patch panels after neutralizing rust,some cars today have body panels that are glued together and that might also be a possibility, some new fantastic materials are available nowdays.

 

If you are just going to patch it to sell it then whatever you feel comfortable working with, probably bondo. but if you want to keep it better cut out ALL the rust and weld a new rocker patch in there.

 

Dogzilla you probably remember the days bodymen would use lead to fix car panels.

 

Lots of suppliers like this ..

1984-2001 Cherokee (XJ) Replacement Panels | Quadratec

www.quadratec.com

 

Well this is a little out of my comfort zone, but after watching some you tube videos, I make try and do it this way. Looks like $380 for 2 rocker panels and the backers. videos say I will need to cut spot welds. Can I do that with an angle grinder?

 

Lots of these also 🤔

 

Another thing to think about is that vehicle probably came from a "salt state", therefore there could be other areas that are starting to rot.
IOW, don't get attached to this vehicle.
Coming from MA, I've seen plenty of salt cancer and failed attempts to fix it.

 

Pacific: Sure do. There was a shop in Hillsboro called Right-Way. If you wanted it done "right," that's where you took your car. I watched them working on a car one day, kinda cool.

 

Fiberglass and resin. Quick and dirty

 

The old timers ..were really good with lead .You have to heat panel enough ..so not to oil can and create a soft spot .They had wood paddles to shape lead .They also used tinned Pennie’s for filling emblem /door handles etc.Lead stuck well and no cracks .Use a zip wheel to cut out rust ,Dremel tool etc.Can drill out spot welds at pinch seams .Spot weld cutter bits are best for this .Premium body filler these days has fiberglass added to reinforce repair .In the old days White Diamond was the stuff .

 

I agree with DirectDrive, don't get attached to this car. You know where there's one rust problem, but you haven't yet discovered all the others.

 

I bought 2 used Grand Cherokee's for my kids to grow up in. Solid entry level vehicles that were for the most part rust/trouble free. The one I bought from Alaska for my son was hiding a secret though. When I went to install a 3" lift on it, we discovered that the lower coil spring perches (F/R) were completely rusted out. Very common problem on them. Had to cut what was left of them off the axle housing, and weld in new ones. All that being said, don't get to attached, and if your going to keep it, cut out the cancer until you find solid steel, and patch correctly.

 

Unibody. Don't just patch with bondo or fiberglass. Truth be told it's probably too far gone already. A full inspection of the undercarriage is needed to determine the extent of the cancer. All the cancer needs removed and surrounding unaffected metal needs treated with something like OSPHO and new metal welded, treated, sealed and painted. Unless that thing has sentimental value, I'd look for a donor body.