Best approach for this repair

[RJB44]

I bought this truck in January of 2007. The previous owner did body work and new paint in November of 2006. This truck was almost flawless when I got it. Since that time, my long lost friend "rusty" has paid a visit. I have two small areas right above the front and rear wheel wheels that are bubbling. The finger test indicates its solid on one side, so I am thinking surface rust under the paint. I have gone to a few body shops, and unfortunately they want crazy $$ for such minor rust repair. I guess most shops would rather stay away from this stuff. I am tempted to try it myself, but with the truck is such great shape all the way around, I am afraid I would do a botch job. I have read about rust bullet and other products. I was thinking I may try the repair, and then have a shop shoot the paint and clear coat, I just can't see paying $1700 for this amount of work.

 

[tRustyK5]

You're not gonna like what i'm gonna tell you...that is not just a little surface rust under the paint. K5's rot from the inside outwards.

Remove the rear tire, grab a flashlight and a small screwdriver and you'll find the real problem. There are drain channels for moisture and debris to drain out from between the inner structure and the outer skin. Debris can't always get out unless you flush it regularly. That debris stays wet and starts rotting the outer skin from the inside.

Take your screwdriver and use it to gently remove and debris you see in the drain areas. With the flashlightyou should see the rust in the areas corresponding to the bubbling on the outside.

The best way to fix is to cut out the affected area and replace with a patch panel and re-spray.

Here is a series of pic's to illustrate. Mine was further along the rust path, but it all starts the same way.

The offending outer skin cut out, you can see the problems extended to the inner structure.

A solid donor patch of inner structure in place. You can see the drain areas, and what a crappy design it is for retaining mud and crap.

Welded and cleaned, ready for a few coats of primer and paint.

Outer patch fit-up begun.

Tacked in place...

Primered, ready for paint pretty much.

$1700 is a lot of money, but it is a fair amount of work to fix right. The good thing about doing it yourself is knowing if any corners have been cut. At $1700 I'd be worried about them just doing a grind and bodyfill on that and spraying over the 'sins'.

Rene

 

[JOES89K5]

cleanup

my blazer is in good shape in these area around rear wheel. the area you have the clamps on to replace has bolts on inside i would like to take this piece out to clean inside inner panel above then rust proof. can this panel be unbolted and removed? the part thats rusted on yours is good on mine. there are spot welds near the drain holes.if i drill out them can that inner panel be removed .are there spot welds at the bolts. i totaly cleaned the underside on rest of vehicle. thanks for any help

 

[wazzabie]

You're not gonna like what i'm gonna tell you...that is not just a little surface rust under the paint. K5's rot from the inside outwards.

Remove the rear tire, grab a flashlight and a small screwdriver and you'll find the real problem. There are drain channels for moisture and debris to drain out from between the inner structure and the outer skin. Debris can't always get out unless you flush it regularly. That debris stays wet and starts rotting the outer skin from the inside.

Take your screwdriver and use it to gently remove and debris you see in the drain areas. With the flashlightyou should see the rust in the areas corresponding to the bubbling on the outside.

The best way to fix is to cut out the affected area and replace with a patch panel and re-spray.

Here is a series of pic's to illustrate. Mine was further along the rust path, but it all starts the same way.

The offending outer skin cut out, you can see the problems extended to the inner structure.

A solid donor patch of inner structure in place. You can see the drain areas, and what a crappy design it is for retaining mud and crap.

Welded and cleaned, ready for a few coats of primer and paint.

Outer patch fit-up begun.

Tacked in place...

Primered, ready for paint pretty much.

$1700 is a lot of money, but it is a fair amount of work to fix right. The good thing about doing it yourself is knowing if any corners have been cut. At $1700 I'd be worried about them just doing a grind and bodyfill on that and spraying over the 'sins'.

Rene

tRustyK5 - Nice work. For the batch panel did you cut it flush or made a joint to the existing panel? What is the trick to get the panels to align correctly and cutting the panels?

 

[tRustyK5]

tRustyK5 - Nice work. For the batch panel did you cut it flush or made a joint to the existing panel? What is the trick to get the panels to align correctly and cutting the panels?

The patch panel doesn't overlap the repair area. I cut the patch panel first, large enough that it was going to easily cover the repair area. I clamped it over the repair area and with a sharp pencil I traced the outline of the patch panel on the truck. Then I removed the patch and trimmed along the pencil line. After that it's just fine tuning a few small areas.

I use the body line as a "datum", and made sure to get the long seam really close to that body line. It's a pretty rigid part of the body so it helps hold things straight when tacking and welding.

I cut the panels using a 5" grinder with a very thin cut-off disc.

Rene

 

[mpio13]

very nice repair!! living on the eastcoast means i'll be doing this soon, and doing it again, and again...and probably again. hahaha, i am tempted to rhino line the inside of the panel before the install, or at least spraying what i can once the welding is done to maximize longevity. i bought my truck 8 years ago, CT winters are terrible on vehicles out here. it had no visible rust when i got it, i've since patched my rear floor pans/"cab corners", replaced passenger rocker panel with the inner panel (came out terrible) and will soon take a shot at the fender.

i work on cars here and notice their overall condition as they age. i can immediately spot a vehicle thats come from down south or out west, they rarely rust very much if at all, as compared to the northeast rust buckets!

anyways, fender looks good, i'll be paying close attention to your repair as i get ready for mine.

 

[GMC Truck]

The patch panel doesn't overlap the repair area. I cut the patch panel first, large enough that it was going to easily cover the repair area. I clamped it over the repair area and with a sharp pencil I traced the outline of the patch panel on the truck. Then I removed the patch and trimmed along the pencil line. After that it's just fine tuning a few small areas.

I use the body line as a "datum", and made sure to get the long seam really close to that body line. It's a pretty rigid part of the body so it helps hold things straight when tacking and welding.

I cut the panels using a 5" grinder with a very thin cut-off disc.

Rene

After restoring many pickup's of the same vintge this is exactly the correct way to fix this rusty area. A proper coating of a good rustproofer will make this repair last a long time!