Generally what I will do in cases like the OP is sand off the surface ..... cut away all the bad metal ..... do everything I can to clean out the inside surfaces and then do what I can to 'flood' the inside surfaces with that stuff.

I've use small " fill it yourself " aerosol spray bottles to get that stuff up inside hard to get places.

You gotta do, what you gotta to do to get done what needs to be done.

At the very least it will buy you some time.

I've done more than my share of rusting rockers like that with the rust not coming back in the repaired areas.

 

Ever rocker I have foudn with rust bubbling out from inside is pretty much toast. Well, in my opinion. Perfect time to cut away back to new metal, and weld in a replacement panel, or better yet, a 2x6

Luckily in my 2K, the PO drilled holes in the top, plugged the bottom with putty, and dumped in oil every fall, drove around, pulled the putty and then drained it. Little plastic plugs fit in the holes. No rust, anywhere.

 

ALL RUST IS SURFACE RUST ......... some starts on an outside surface, some starts on an inside surface.

 

cut the entire rocker out, weld some box steel in there and use it as a slider.

 

Yeah and then there is one thing you can't FIX
They walk among us!





By far the best way to go on an off road XJ!

 

I had very similar spots on mine and after grinding it down carefully I still went through the metal on 2 spots. Used fiberglass and POR15 thinking it was only surface rust but it came back pretty quickly and now I have a couple bubbles under the POR15 (which holds on great a part from the interior rust which I cant apply onto).

Just wait till you're able to fix it once in for all. When I get a welder I will attempt 2x6 replacement, until then I tried to patch the holes as much as possible to avoid more salt and debris to get it.

 

Rockers are eaten up with rust on the inside.

 

Yup .... it starts on a hidden surface and works its way out to where it is visible.

I like it when people come to the shop and ask about 'bubbles in the paint', when I tell them it is rusting out they tell me there is no rust!

Scratch away the bubbles ..... rust.