I'm in the process of trimming my back fenders but there is now an open cavity for mud and water to get in. I've seen some people seal it off, but what do yall do it with?

 

Weld. Or cut and fold is normally what people go so that doesn't happen

 

Well it's too late for me to cut and fold so I guess welding is the only option?

 

after you weld it shut you might want to put some expanding foam just to be sure

 

Expanding foam holds water.

 

I did the same thing, i just used sheet metal and riveted it in place. I used silicone when i pressed it into place. You can fold it right behind the fender flare then reattach the flare. You'll never worry about it again.

 

i cut mine up pretty far and folded the inner sheet up even with the outer and welded it up. yours dont look too bad if your good with a welder. it will just take time.

 

They have expanding foam that is used in landscapping for ponds and waterfalls. It's a black foam and its water proff, give it a try. It's sold at Lowes and Home Depot.

 

i had the issue of rust when cut and folding mine so for some of the holes i just got some jb weld and put it in there. once dry i sanded it down to look flush. works great and keeps water out. i will be going back to it soon with the waterproof spray foam crap to make it a little better with sealing and strenght in the metal

 

I welded mine up and then used seam sealer on the inside and out.

 

Cut / Fold / Weld / Seam Sealer / Bed Liner on mine.

 

Yeah you gotta be careful when trimming the rear. I usually don't take it any higher than the first factory "lip". You are breaking the unibody welds when cutting further up, so re-welding is the only safe and logical solution IMO. Foam will keep debris out, but just cross your fingers that you aren't in accident or rollover, which could ruin a straight body and your day!

 

I had to take mine extreme, PO messed up the fender trim job. He used tin snips and it just looked plain bad.

Hidperf, did you add any angle iron or anything when you welded it up?

 

uh oh. I used expanding foam. 0_o

 

My lower panels are rotted out and I get mud inside on the passenger side lol. The top of that indent inside is open.