Inner Rocker / Floor Section

[Dustydog]

I am replacing the inner rocker panel on my 1970 GMC. My question is should I overlap the replacement panel or cut both the floor and replacement part and butt weld them together? The rust was only on the inner rocker, not on the floor. I have trimmed the original inner rocker back to where it joins the floor. The replacement part is temporarily on top of the original floor. Everything seems to fit well, I have test fit the outer rocker and even had the door on to check the gaps and all seem fine.
Looking for any suggestions on how to proceed.
Thanks!
Dusty

[Dagr8npwrfloz]

Subbed, I've heard butt joint, but they were talking doors and fenders... Any different where one would be stepping? Can't wait to hear from the gurus...

[2002yanks]

cut the floor to fit and weld it in. if you overlap you are leaving a place for water to get trapped and start rusting all over. just tack it in and tack the rocker in and check door fitment before final welding anything.

[Steven R]

I am no professional but overlapping is not a good idea IMO as it tends to trap moisture and promote rust. I would but weld if at all possible.

Any place where you have a lap joint it provides a place for moisture to be trapped. No matter how tight you get a lap joint to fit up there is always gaps and water will always find a way to get it. Just take a door skin apart and even with seam sealers on the seams there rust in there...

[FirstOwner69]

I think if you overlap the panels you'll create a cavity that may collect moisture.We all know where it goes from there. Butt weld it.

[hugger6933]

Butt weld and here is how. When you cut the inner rocker and other parts out[ A and B pillars]cut them just below the hinge bolt holes on the lower door hinge. Also cut in along that line and remove the footwell panel up about that height too. you will see why once done so that the inner rocker and floor piece can be slid right in from the outside without any struggle. Now after that is done trim back the inner rocker just past where the screw holes for the carpet trim piece was [unless time has done this for you] then everything will start to make sense. You can then lay the new floor piece right on top of the old one.
Then you can take your cutting device,[I used the plasma cutter on one side but make sure your tip is clean or the cut will be a little ragged looking]or better yet the 4 inch angle grinder with the metal cutting blade or just a plain old die grinder. This will be the most likely tool that everyone would feel best with [as the 4 inch grinder is kinda hard to control]. Then cut the TOP& BOTTOM at the SAME TIME. Then you have a gap about the thickness of the cutter blade and then start you some screws in the cab mount to hold it in place [Be sure to drill some holes for spot welds in those areas]and then welder up!!!!

[hugger6933]

Sorry for the second pic I thought it was better than that

[hugger6933]

Let me clarify just a tad, cut along the edge of the new floor piece[ it will give you a nice clean line] If you need any more help holler and I'll be glad. I'm back in town and near my computer.

[sduckworth13]

The main thing is measure, measure, measure, then weld your patch in. The door gap should be 5/32 around the sides and top. The bottom of the door gap should be 1/4 from the lip of the outer rocker, so there is very little room for error. It might be not that big of a deal for body guys that do it all the time. If your doing this for the first time just go slow and measure everything.

[Dustydog]

Thanks everyone, you all confirmed what we thought. Now to get started on the work!
Thanks again, I am sure we will have more questions!

Dusty