1970 Chevy Chevelle Malibu Project - Project XS Chevelle, Part One-Body Cancer Treatment

Here's what's left of the original floor next to the new Goodmark floor, so you get an idea of how much metal had literally rusted away, and why the Chevelle's structural integrity was not good. The new Goodmark floor comes as one unit (you can also purchase separate area pieces depending upon what you need) and includes the factory floor braces already welded in, so you don't have to worry about transferring your old ones, or making new ones to replace rotted ones, like in our case.

A little known fact is that GM used galvanized steel for the inner and outer rockers on the '70 Chevelles and Malibus, along with other cars. This gave them extra protection against corrosion, and it's why the outer rockers on our car were just fine and only needed some clean up. The inner rockers had rusted just enough though to need replacing, as you can see here where a floor brace attaches to the inner rocker. Since Goodmark sent us new inner rocker pieces, this was not a problem.

To get an idea of how to go about replacing the inner rocker, Jim compares the new Goodmark piece to the factory one. After some examination, we had to step back and figure out how to put everything together since the floor pan attaches to the inner rocker.

With everything figured out, Tommy goes to work with the air chisel breaking loose the factory spot welds so we could remove the inner rocker, and at the same time protect the convertible reinforcement floor brace seen just above the chisel.

With the welds broken, the inner rocker popped right out, and we got a chance to see what the inside of the outer rocker looked like.

While the car sat over the years, rodents had taken up residence in the rockers, as evidenced by this lovely mouse nest. Despite this, the outer rocker was in great shape, and didn't need to be replaced thanks to it being galvanized steel. We wish GM would've used the same steel for the rest of the car.

After welding in some pieces of box steel tubing to help support the rocker structure while the new floor and inner rocker was installed, the whole area was painted with special zinc primer that protected the rocker and steel supports from rust, neutralized any surface corrosion on the rocker itself, but still gave us a great welding surface for the new inner rocker because of the zinc content. You don't want to use a product like Por-15 here because it'll hamper welding the new inner rocker. The paint is readily available at automotive paint shops and catalog dealers like Eastwood.

With everything all set, the new floor pan/inner rocker structure is slid into place for alignment and spot welding. Because of the way Chevrolet built these cars at the factory, and the condition of the body, we had to install the new sheetmetal this way to make sure everything was lined up structurally and would support the body correctly when we started to replace other body parts. In our next installment, we'll be tackling the repair work on the toe boards, cowl, and windshield area.