Chevy Truck Cab Modifications - Unholey Transformation

...A quick tap of the knuckle on areas suspected of a quickie job will usually tell you whether or not there's a layer of filler concealing any rot, such as seen here.

While removing the cab from the chassis is not mandatory (it will, however, make the job much easier), the doors will have to come off for any hinge area work. Once that's done, you'll want to drill out all the factory spot welds along the pinch seam before cutting.

To ensure you don't cut out too much material (and to avoid having to weld in a contoured area), trace the patch panel from the backside and subtract a half inch or so. Since butt-welding is recommended, you can trim excess material off the patch itself to align everything, or trim a little from each-whichever works and doesn't leave you with a huge gap!

With the important and integral pillar filler in place, the lower doorjamb (firewall/cowl) piece can be replaced. Note that even though the fender mounting hole is slotted, you will want to make sure it's right on the money or as close as possible for obvious reasons.

The important part here is not so much perfect sheetmetal alignment as it is perfect hinge pocket placement, as you don't want the additional chore of dealing with a heavily misaligned door later on. Take the time to plot the location and mark appropriately.

Even if it means temporarily hanging the door before proceeding, do it! The last thing you want is having to cut your freshly welded patch panel and start over. Once you do get everything welded up nicely, grind down the weld beads first until they're flush with the existing metal-don't just run your grinder back and forth until the entire area's smooth.

Since the gusset portion of the hinge area was beyond salvageable (and not available in repro), Bill cut and bent his own piece of sheetmetal to retain strength.

Save for the upper cancerous area, the hinge sections on the cab now look as though they've never seen a lick of road salt....

...While aesthetics aren't your number-one concern (lap-welding and visible beads are OK), the precise placement of the fastener holes is.