1967 Pontiac Lemans budget build - Episode eight, floor pan and rockers, part one - updated 02/28/2024

Episode one, introduction.

Episode two, trunk panel install part one.

Episode three, trunk panel install part two.

Episode four, door rust repair.

Episode five, tail light panel and rear crossmember.

Episode six, passenger quarter panel.

Episode seven, driver's quarter panel.

Episode eight, floor pan and rockers, part one.

Episode nine, floor pan and rockers, part two.

Episode ten, frame repair and prep, body drop.

Episode eleven, radiator core support and miscellaneous rust repair.

Episode twelve, trunk repair and more miscellaneous rust repair.

Episode thirteen, fender and inner fender repair.

Episode fourteen, panel prep and block and prime.

Now comes the most intimidating job of the whole build, the floor pan and the rockers. This episode will cover the removal of the body, the cutting out of the floor pan, the repair of the toe pans, the firewall body mounts, and the kick panels. Episode nine will cover the installation of the rockers and the new floor pans.

Here's what I started with:

Eww. There's a lot of damage, mostly isolated to where the cross bracing is connected, which means there's a lot of good metal remaining. Once again I was momentarily tempted to simply repair it. But considering the hours involved, the cost and hassle of new cross braces, as well as the possibility of hidden rust, I opted for replacement. I'm glad I did since there was a lot of hidden damage, particularly at the lower cowl and where the cross braces were attached to the inner rocker. 

Here's the new panel:

This AMD product was $554 from Summit Racing (at the time of purchase in mid 2023) and it's a screaming bargain. All the cross bracing is already attached, it has the seat belt mounts and the capture nuts, and the inner rockers are already in place. I'll need to transfer the seat mounting brackets to it, however. 

If it's as well-engineered as I think, it should be a sort of pop in and weld.

We'll see how that goes.

So to get started, I needed to get the body off the frame. I tacked in a couple of pieces of angle iron across the door openings to keep things from moving. It's also a good idea to cross brace side to side to keep the body from widening. However, I watched a youtube video where the guy left out the cross brace. He wanted the body to be able to widen a bit so as to make the installation of the floor pan a little easier. According to this fellow, the door jambs can be ratcheted back into place before welding the pan.

First I removed the front sheetmetal:

You can see here I've already started the body raising. About the pallet: The steering box is gone which means the center drag link just flops around and the front wheels can't be steered. The pallet has casters mounted to it so I can move the car around.

Next, the rusty body mount bolts needed to come out, a task I dreaded. I already knew they were in bad shape from from when I rebuilt the four mounts in the trunk floor. However, it turns out that the factory put in rubber mounts with no bolts in a total of four of the mounting points (the pair near the rear spring pockets and the pair near the rear seat). You can see one of them in the center of the pic below.

So that left six mounts - the two front seat area mounts and the four mounts at the firewall.

The mount on driver's side seat area was completely rusted out and not attached to anything. The passenger side was still contained under the floor panel and not visible, so I cut out a square out of the floor panel above it and found the cross brace was full of rust and debris. I just cut it out.

Lastly, the mounts at the firewall. Surprise, I found that the two on the driver's side were already broken off, either by a previous person twisting them off or maybe they just failed. The two on the passenger side were still attached, but the cage for one of the capture nuts was just laying there loose inside the cavity and actually in good condition. You can see it center left in the pic below. I just cut through the rubber with a reciprocating saw, and the other twisted off.

Here are the sad remnants:

Frankly I'm surprised that so few of the mounts were actually holding something. I don't know the car's history but I do know it led a tough life. It's scary to think that someone might have been driving the car while the body was barely held onto the frame.

So the body is now free of its mounts. I also had to clear out some wiring and the parking brake cable. My car did not have the steering or the master cylinder installed, and the engine was long gone, so a lot of things someone else might have to remove were not present.

I jacked the body up off the frame with my floor jack, going back and forth between the back and the front, and slipped a couple of 4x4s under the body. I blocked up the ends of the 4x4s with stacks of short pieces of 2x6s under the jack stands: 

The body had to be lifted high enough to clear the raised area of the frame over the rear axle. I took off the tires for more clearance, but the body still had to be uncomfortably high in a position of uncertain stability: 

I dragged the frame out into the driveway:

It was at this point I remembered I have a chain hoist and a cherry picker. Sheesh. The job would have been so much easier. 

Now I needed to put the body down in such a manner as to leave the underside of the floor unobstructed. For the front I put it on jack stands where the lower fender bolts connect, and for the back I built a sawhorse out of some scrap wood:

I took some time to get the body perfectly level side to side so I could make sure things wouldn't get out of alignment. I also left the doors and trunk on.

In a later episode (ten) I will drop the body back on the frame temporarily. Then it will need to come off again for finish welding and undercoating. I devised a better method for raising the body, which I will cover in that episode.

Now it's time to plan my floor panel cuts. The panel is spot welded under the rocker flanges front to rear on each side, under the trunk cross brace, to the wheelhouses, and to the toe boards and inner cowl panels in the front. Also, the front and rear door jambs are on top of the rockers, which are on top of the floor pan. This means the floor pan is under two layers at these points. 

The temptation is to just cut everything out at once, but that might mean cutting something you needed to keep. So I cut in sections, leaving a couple of inches of waste metal all the way around the perimeter. 

I marked my lines on the old floor pan with a sharpie and started cutting:

Here's the result:

Here's the remnants:

I'll be saving these because the various brackets will need to be transferred to the new floor panel.

With the old floor panel out of the way the way is clear to see what I'm faced with. The driver's side front rocker area:

Yes, it's as bad as it looks.

And the passenger side:

These are major structural points, so I took a lot of time to re-create them with all the layers. 

The new floor panel includes the inner rockers, but they do not go all the way forward to the lower fender mount. That little square corner on the lower lip you see (center, above pic) is where the new inner rocker ends.

In addition to this, both the driver and passenger toe boards are rusty:

I probably could have filled a couple 5 gallon buckets with the residue removed from the rockers, the floor panel cross braces, the lower cowl areas, and the lower parts of the quarters. All of the cavities were filled with mud, debris, and leaves. 

So at long last we are able to diagnose the reason the car is rusty. First, mud. As the mud accumulates over time it does not drain through the drain holes and plugs them up. Then when it gets wet it simply sits there and causes rust. 

Second, the leaves means it was parked outside under a tree. Third, there is evidence of white crusty deposits on the surfaces to the rear of the car, which means salted roads. This last thing is why I'm being so careful to replace bad metal and prep the original surfaces. If salt is simply covered up it rusts the car again.

Ok, back to the repairs. You can see in the above pics that I have already removed the remnant of the old floor from the toe panel pinch weld, revealing rust damage to the flange. Drilling spot welds can lead to more repairs, so I used a technique similar to what I did on the tail light panel, a chisel and a pair of vice grips. But this time I actually did use the spotweld cutter, but only to weaken the area around the spot weld. I did not go through the whole first layer. This allowed me to roll up the sheetmetal and break the spot welds a lot more easily. I ground the spotweld remnants flat and dollied the flange smooth.  

The rusted toe panels were addressed next. I marked out my cut on the driver's side and then took the cutting disk to it:

I used the cut-out piece (seen on the right) as a pattern for the replacement.

As soon as I started cutting I realized I was going to get a substantial side benefit: Access to the cage nut cavity. On the firewall side it's a pretty small hole so having this access was a real bonus. So I cut open one of the sides of each cage with my Sawzall, pried them up and slipped the cage nuts out. I drilled out the rusty remnants of the bolts from the cage nuts and ran a tap through them. 

Good as new. 

I wire brushed and sanded as best I could and painted on the POR15: 

I used a little parts cleaning brush and a q-tip to get into the cracks and up into the cavity. I reinserted the cage nuts and welded the cage back together.

I used the old piece to make a patch. Here's the welded driver's side:

This was a complicated patch because of the compound folds. In order to form this piece I welded the top seam, then massaged the left side with a hammer until it started to move into position. I added tack welds as the patch started to line up, then moved further down until I got to the bottom. But even though I cut my patch oversized (or so I thought), it came up short as I massaged it into position. This left me a 1/4" gap at the lower seam. I filled in the gap with a thin strip of metal, which is the reason you see two rows of welds there. 

I also fixed a couple of places on the flange while I was here. 

For the the passenger side there were several stamped ridges that needed to be duplicated:

This shows the old piece laying on top of the new metal. 

Here's the view from the top:

It's a pretty good match. I accomplished this by hammering a piece of pipe that matched the diameter of the recess. 

Here's the patch welded in, along with some repairs to the flange:

Here's the finished toe panel:

I did not repair the toe panel's connection point to the lower cowl because I wanted to first repair the lower cowl, and also to get the floor panel installed so I could then see what might need to be moved.

Now for the kick panels. There are multiple layers here. The inner cowl covers the whole hinge area down to the lower flange of the rocker. It is spot welded to the forward extension of the upper rocker as well, plus at the door post opening and the firewall. Then on top of that is a reinforcement panel that is spot welded, which goes forward under and up to the rear of the vent opening. And there's an intersection point between the reinforcement panel, the floor panel, the toe panel, and the upper rocker extension, all spot welded together.

The more I cut away from the reinforcement panel the more rust I found on the inner cowl underneath. What a mess. I kept cutting until I found good metal, which revealed the inner cowl cavity and the lower hinge attachment point. The lower hinge cage was rusty, so I repaired that. I wire brushed the entire area and gave it a coat of POR15, reaching up into the recesses of the inner cowl cavity as far as I could:

It's a little hard to see, but the horizontal piece in the middle is the front extension of the upper rocker, and the white-ish dot in the center is a hemispherical depression in the sheet metal of the inner cowl panel, purpose unknown. You can also see how I have not yet completed the flange that connects the toe pan to the inner rocker.

I left hemispherical depression in place and cut the new piece around it. You can also see how the outer rocker continues forward to the lower fender mount area and forms the major part of the structural enclosure where it mates with the inner rocker.

I fashioned a piece of sheet metal for the inner cowl, which I spot welded to the upper rocker extension and the door jamb:

You can see a little better that hemispherical depression that I cut the patch around. 

I then cut a piece to finish out the reinforcement panel: 

Jumping ahead several months, I began work on the upper portion, hidden under the temporary brace. The brace couldn't come out until the floor pan was in and the body was back on the frame, which I cover in future episodes. 

First  I cut out the rust:

The flange was still good so I started fashioning the first patch piece, which has a vertical raised rib:

I did this by opening the jaws of my bench vice about a half an inch and laying the patch across the opening. I put a long bolt  on it and hammered on it to shape the rib. Then I drilled some spot weld holes.

I POR15'd everything:

Welded and ground:

The final piece was the rest of the reinforcement panel. I cut a patch, welded and ground it, and puttied the seams to smooth them:

I sanded it out and primered it. Good as new. 

Next I started work on the passenger side. I had hoped it wasn't as rusty as the driver's side, but it kinda doesn't matter. It all still needs to be cut up and reconstructed.

First I cut out the rusty metal:

Here you can more clearly see the forward flange of the rocker, as well as the uncompleted toe pan flange area. 

I welded in the first layer:

Those black spots on the toe panel are the trail of POR15 I dripped when I was painting the inside of the cowl.

I let the lower edge of the repair piece run wild until I could get the passenger outer rocker installed, at which point I'll trim it. 

Next comes the reinforcement layer:

This side came out better than the driver's side. I'm not quite sure how it was supposed to look since it was all rusted away, but I'm not too worried about that. The frame and the kick panel will eventually hide all this. But it will be strong, and it won't rust again. 

Next episode: The rockers and the floor panel.