Common rust issue everyone needs to check for!

[OneofFew]

Guys, my Tahoe spent too much time in salt-land. When I got it, the rocker panels were already terrible. I had a suspicion as to the cause of rocker panels rotting out from the inside and went to investigating a bit yesterday.
In the rear wheel wells, maybe 4 inches above the plastic skirt that runs alone the bottoms of the wheel wells, there is a seam on the front side. rust may not be evident and covered in dirt, but once this seam gets compromised, the rockers can literally fill up with water!
What I did as a hillbilly fix, was to use a piece to rubber (truck) mudflap cut to size and used self tapping screws to cover that area. Of course cleaning up the rust and caulking under the mudflap is the way to do it.

 

[OBScenity]

I had this problem on my '02 and it resulted in rusting through the doglegs of the rear door frames before I caught it. That seem doesn't exist on my '05 though - they replaced it with a single piece plastic wheel well. What year is yours?

 

[CountryBoy19]

I had this problem on my '02 and it resulted in rusting through the doglegs of the rear door frames before I caught it. That seem doesn't exist on my '05 though - they replaced it with a single piece plastic wheel well. What year is yours?

Thanks for that, I was looking at my '05 wondering what he was talking about and then I couldn't remember where the thread was to ask for clarification...

That being said, the rocker panels do still rust out. Does anybody know how to slow the progression of the cancer in the rocker panels?

 

[MARSOC-RAIDER]

Does anyone have advice for repairing a rusted driver side rear wheel well and is also part of the rear driver interior door jamb arch (where the seat belt is bolted into that area)? I cut the portion out from a junk yard looking to somehow weld it on. Any suggestions or pictures PLEASE.

 

[89Suburban]

This was a notorious issue on the square body Suburbans. The well seam would rust open and split, then all the shit starts filling up the rear quarters and start rusting from the inside out. Being I owned many of them I’ve seen some with 4” of sediment built up I’m some quarter panels. Nobody ever thinks to check those seams until it’s too late usually. And trying to weld them up with new or donor steel is a major pain in the balls.

 

[MARSOC-RAIDER]

Thanks for responding. Any suggestions I went to the Junkyard and Got the Dog Leg or Wheel Well arch that and cut it below the door lock on the body and to the middle of the rocker panel on the floor and along the weatherstripping seam. Do you have any advice on how to go about putting this on? should I just MIG weld it? cut the old out with a plasma cutter ? Thoughts advice much appreciated

 

[89Suburban]

Thanks for responding. Any suggestions I went to the Junkyard and Got the Dog Leg or Wheel Well arch that and cut it below the door lock on the body and to the middle of the rocker panel on the floor and along the weatherstripping seam. Do you have any advice on how to go about putting this on? should I just MIG weld it? cut the old out with a plasma cutter ? Thoughts advice much appreciated

I am not a not a certified body repairman just winged it. Not sure what advice I can give you. I just used a cheap MIG with flux core wire. Made most of the inner panels myself out of sheet metal and reproduction outer skins. I CAN advise that if you can weld in some backing splice panels or tabs if you will, it helps back up the panel joints and give you some extra to weld to. Drill some spot holes, then cut a tab piece and place behind the existing panel edge sticking out a 1/4" inch or so and tack weld through the drilled holes. Whatever my booger welds could not seal got slathered with seam sealer underneath or Bondo on the outside lol.

 

[zraffz]

I currently have my Tahoe torn apart for repairs and figured I'd take care of all of the rust. My truck lived in MA for 12 years and is now over 5 years in NJ.

Key rust spots:
Rear inner wheel well seams
Rear section of rear passenger doors to inner wheel well arch
Lower rear quarters
Inner rockers
Outer rockers

I would also like to point out that these frames have a terrible design that causes debris and sediment to get trapped. In front of the rear axle (where the fuel tank is), the frame shoots up at a 45* angle. My frame is rust scaled in this area on the driver's side. I blew the frame out with compressed air and picked out the larger rust flakes.

On my truck, I am wire wheeling the frame, painting it with bridge primer & paint, plating the rear sections as a safety measure from the control arm mounts to the nearest body mounts on both sides and using Eastwood's internal frame paint. This would be a impossible to repair without removing the body if I didn't have the 3" body lift and coincidentally have to cut the rockers off for repairs.

I caught my frame in time. I smacked it with a hammer and have a small 1"×1" spot the frame dented in this section.

 

[zraffz]

As far as body work goes, I use a Hobart 140 mig welder for sheet metal and an Eastwood 250 mig for anything more structural (like plating the frame).

Buy a used 130-140 amp mig welder with gas shielding and go to town. I always try to cut below the body line seam to make blending paint easier; as long as this area is not damaged or rotten. I then tack weld the new panel and build it up with small tacks to avoid warping.

 

[OneofFew]

Mines an 01. I guess they changed the design for the 05s.