1967 Pontiac Lemans budget build - episode two - trunk repair, part one of two

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.

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In this episode I start the replacement of the rusted-out trunk panel. This will be in two parts. This episode will be the preliminary repairs, like the wheelhouses, and episode three will be the actual installation of the trunk pan. Future episodes will feature the passenger compartment floor panel, the rockers, and the rear quarters.

Here's what I started with:

There are two ways to approach the trunk pan replacement:

• The whole trunk pan is available, which goes from the rear seam of the passenger compartment floor pan all the way back to the spot weld seam where the tail light panel connects, and to each side where the trunk side-drop panels connect. As far as I can tell, the full floor pan cannot be installed from the top unless the taillight panel is removed. Nor can it be installed from the underside, if the body is still on the frame. Again, as far as I can tell. 

• Or, you can buy a partial trunk floor in pieces as a kit, which was my choice. That's a lot cheaper. The new pieces go all the way to the trunk side-drop panels on each side, but only part way up the ascending part of the both front and back of the trunk area. 

I chose the multi-piece kit because I thought the rest of the trunk pan was good (the part that goes over the rear axle and the part that intersects with the tail light panel were not part of the kit). But actually, it turned out that both these parts needed repair. And, because I replaced the rusty tail light panel, that obstacle to installing the full trunk panel was no longer present. So all this meant I did additional work that could have been avoided with the full panel option. 

Oh well. I bought the multi-piece option, so that's what's going in. Here's what I received:

The replacement pan is in three pieces, plus there are the two gas tank braces that run front to back and two body mount braces that go from side to side to connect to the body mounts just behind the wheel houses. 

So the first step was to draw out the rough cuts with a sharpie, leaving plenty of extra metal which can be trimmed to fit later. I made the cuts:

The trunk floor was so bad it only took about 30 seconds to remove it. It's about one step from from being just a pile of powder:

So now I have a gaping hole to fill, but removing the floor revealed more damage: The wheel houses. You can see the rot right behind both of the rear tires. The driver's wheelhouse rust went all the way up and over the rear axle:

I decided to divert my attention from the trunk to this repair. Now, ordinarily a pro shop building a car for a pretty-boy-with-a-checkbook customer would replace the inner and outer wheel houses. But not me. This is a budget build so it's got to be fixed.

The area above the vice grip was tackled first. The rear of the wheel house actually ends short of the lower edge. The factory put in a separate extension panel that completes the lower back area. I recreated that, including the seam, and then continued the repair forward over the axle all the way to where the rust-out ends.

I made a cardboard template out of a cereal box, making sure to leave it a little big. I cut the patch and hammered it into a curve on the bench vice. To do this I opened up the jaws a couple of inches and laid the metal over the gap. I lightly hammered it which allowed it to begin to arch downward between the jaws. After several test fittings, adding a twist, and trimming the edges, it fit nicely. 

I cleaned up the original sheet metal around the welding area with a flap disk and started tack welding. I worked my way around, spacing my stitch welds so as to not overheat the metal. After filling in the stitch welds into a continuous bead I ground the welds smooth:

The idea is to finish the repairs well enough that a little bit of filler and some seam sealer will completely hide the repair. No slathering of black goo will be in this panel's future.

You can see in the above pic (right) where there was more rust at the quarter panel lip. In order to get a fuller view of the damage I decided to take off the wheel opening trim. I found there was nothing underneath it. It was all gone, see below pic. The rust is in both the lower extension panel I had just worked on, plus part of the outer wheelhouse above that. 

So I got to thinking: I had already put a repair in the lower extension panel. Now I am faced with the need to replace more than half of the rest of it. So rather than have a multi-pieced extension panel with just a sliver of original metal I decided to just replace the whole thing .So I drilled out the spotwelds and and took the extension panel out:

You can see the trunk side drop panel has a bit of rust but was surprisingly solid, even though the lower lip of the quarter panel was rusted out. 

Inside the trunk I pried off the remnant of the rusty trunk pan that still attached to the side-drop panel and wire brushed it. That was in preparation for installing the left third of the replacement trunk panel.

Here's the view from the trunk side (before removal of the pieced-together lower extension):

So here's the completed repair:

Kinda hard to tell from the pic, but it came out pretty well. I finished the open area, but I did that after I removed the quarter skin in a later episode.

Here's the completed area, from the trunk side:

I also started on the passenger side:

It's hard to get a good picture sometimes. This repair actually looks good in real life. What you see is the start of the wheelhouse repair, and the wheelhouse extension piece.

Back to the driver's side. After I cut out the remainder of the rust out of the wheel house I test-fitted the left trunk panel:

The trunk panel kit came from adealsap on ebay. I don't know who their supplier is, but the panel fitment isn't very good.

First, there's a 1/2" gap around part of the wheelhouse, which I suppose could be partly because I shaped the curve of my wheelhouse repair incorrectly. In order to fix this I cut the flange on the trunk panel and move the lip closer to conform to the curve. 

Second, the new panel's pinch weld flange runs out past the flange on the trunk side-drop panel, almost touching the quarter panel. So I had to slice it from front to back, remove about an inch, and weld it back together:

Third, there is an up-slope formed into the side-drop panel where it connects to the wheelhouse. This upslope is a few inches long, but on the replacement panel it's shorter. This means the panel cannot be lowered down enough to rest on the spotweld flange on the side drop panel. So I cut the trunk panel on the blue line (see two photos back, above), which allowed the panel to be lowered onto the side drop panel flange. Then I welded in a piece where the cut spread apart.

Three more reasons to buy a full one piece pan.

Now it's time to turn to the rusty lip that goes up over the axle. First a rough cut to where there's good metal:

The rectangle on the top left is the opening at end of the cross brace. There is a small flange on it, pointed down, that is still solid. To that I plug welded a new piece that became part of the trunk floor flange. That flange drops forward along the wheel house on the left, and continues to the rear where it descends down to the point where it will connect with the replacement trunk panel. I filled in this part with new metal, detailed below. 

Also, notice how the opening I cut is wider to the right. When I cut out the rot the trunk floor dropped. So I measured how high off the frame the passenger side of the panel was (About 1 1/4"), and pushed a big screwdriver under the original trunk panel on top of the driver's frame rail until the panel was the same height. 

I tried to retain the original trunk flange seen in the above pic, but it turns out it was just too thin where the seam sealer used to be. Makes me wonder what seam sealer does, since a lot of the rust in the car was found under seam sealer. So I cut it off, cutting about an inch into the existing trunk pan, so as to find good metal.

This created the need to make the trunk panel repair combined with the flange repair. So I bent a piece of sheetmetal (about 2" x 10 1/2") down the middle lengthwise to create the new flange and to fill in the missing part of the trunk, and clamped it in:

This took a bit of trimming to get it to fit to the existing trunk floor. 

I went inside the trunk and stitch welded the new piece to the trunk pan. Back in the wheel house, I made a short piece to extended the flange to the front. I wasn't quite sure how to shape it, but I knew it covered the end of the cross brace:

The gold color is weld-through primer. I drilled two holes to plug weld it to the cross brace flange. 

In the lower left corner of the pic you can also see some more rust in the front of the wheelhouse. That also will be tackled later.

Here's the completed flange, all dressed out with the flap wheel:

And you can see the big screwdriver I used to raise the existing trunk floor up to the proper level. This made the gap pretty even all the way across. 

This is the inside of the trunk:

The next step was to create the piece to complete the wheel house above the axle. I had the foresight to make a tracing of the shape out of a piece of cereal box before I cut out the rust:

I cut along the lower edge of the pattern, which gave me the outline of the bottom edge of the panel, then made an oversize cut up and around the cardboard. Then I trimmed it down until it fit to the wheelhouse. It looks like this, tacked in:

I finished it by filling in the rest of the stitch welds, trimmed along the lower edge a bit, and filled in a couple of small areas missed by the big patch: 

It's hard to tell from the photo, but the repair came out pretty nice. 

I also did a couple of small spots on the passenger side, but I won't be supplying a step-by-step, since it's mostly a repeat of the driver's side. Here's a pic:

You can also just see the finished rear part of the wheelhouse (left).

I also patched a hole in the top of the passenger wheelhouse:

And ground it smooth:

You can see there's quite a bit of rust damage to the outer wheel house. We'll get to that in a later episode.

The next step was to fit the diver's side body mount brace. This brace runs under the trunk floor perpendicular to the frame rail, and connects the trunk pan to the frame mount behind the wheelhouse. On this side (driver's) the frame mount was rusted out where the rubber donut mounts. So I ground out the mounting hole in the frame until I found good metal. cut a piece of heavier metal from an old Dish Network satellite bracket, and welded it in:

With that solved it came time to address the brace itself. The location of the cage nut was off by over an inch! So after taking careful measurements I cut out a rectangle around the cage nut and moved the cage nut inboard. I welded the cut out piece donated by the new location into the new location and filled in the vacancies with new metal as needed:

It now fit perfectly to the wheelhouse and to the body mount location. I put it in position on the frame with the rubber donuts and the body mount bolt, leveled it, and then put on the trunk panel. Everything lined up, so I zip screwed the brace to the trunk panel. I then pulled the panel out, removed the zip screws, and wiped down the interior surfaces of the brace and the panel with acetone. I taped off the areas where I didn't want POR 15 and gave the interior surfaces a good coat. I then sprayed a narrow band of weld-through primer and drilled some plug weld holes around the perimeter of the brace. I reinstalled the zip screws and plug welded the brace in place.

The driver's side trunk panel modifications are now complete, finally. However, I did not install it until the other parts of the trunk were ready, because when I was working in the trunk I sat on a stool in the big open area. Closing off too much of the trunk would make it harder for me to maneuver in there. 

The next problem to tackle was the rear body mount cage nuts. A cage nut is a square chunk of metal with a threaded hole. It is enclosed in a "cage," which is basically a formed piece of sheet metal spotwelded to the body panel. A long bolt is passed up from the underside of the frame, through a couple rubber donuts on either side of the frame mount, up through a hole the body panel, into the cage nut, and protrudes up through the cage's hole. Usually cage nuts are hidden inside body panels, which means that once the trunk pan is installed they are no longer accessible. So if there's a problem it's better to find out now while the area is open.

And there was certainly a problem.

I didn't get a "before" pic, unfortunately. Both of the rear body mount bolts were badly rusted, as were the cages. So I cut the head off the driver's side bolt underneath the car with my angle grinder, peeled back the remains of the cage on top, then pulled the headless bolt out the top. The structural panel was in pretty good condition so I wire brushed it and covered it with POR 15.

As is my habit I don't buy what I can salvage or make myself. So that means cleaning up the old stuff. But could I get the nut off of the old body mount bolt? It looked pretty bad. The threads protruding out the top were heavily rusted, and the part of the shaft that passed down through the rubber donut was half gone.

I clamped the nut in the bench vice and put a vice grip on the remains of the bolt shaft (the part that passed through the donuts), then  I applied heat only to the nut with a propane torch. After a minute I gave the bolt a twist clockwise and it gave! The reason I went clockwise is that turning this direction rotates the bolt farther into the nut, which moves the nut to the area on the bolt where there are no threads. That exposed more of the threads formerly inside the nut. I cut the bolt on those threads, and now the nut could be threaded off rather easily. After running a tap through the threads and giving it a good wire brushing it was good to go.

The passenger side was not as cooperative. The bolt twisted off so I had to drill out the center of the nut. I was careful and didn't damage the threads.

For the cage I used a piece of heavier gauge sheetmetal. The cage didn't have to be perfect, just functional. A bit of bending in the vice and a hole in the top for the bolt to pass through and it was good to go: 

I coated the inside with weld through primer and positioned it on the panel. I put a new bolt up through the rubber donuts and centered the nut within the cage. A couple of tack welds and it was done:

I wire brushed the whole area and gave it a coat of POR 15:

So, the two rear cage nuts are done, and the two trunk mounts that came with the replacement trunk panels are done, but there's 10 more frame mounts on the car. Hopefully they will go well.

It turns out that that the two mounts above and just forward of the rear axle didn't have bolts at all! I saw the cage nuts inside the cross brace when I was working on the wheel houses, but when I crawled under the car to remove the bolts there was only a rubber plug in the frame. That turned out to be part of the body mount donut, but without a hole through the center. The body just rides against the donut.

Quite a surprise, but that means two cage nuts I don't have to fix.

Moving towards the front, the four floor pan mounts came out with the pan so they weren't an issue (covered in a later episode). This left the four firewall mounts, but those cage nuts are exposed in the engine compartment. So that narrow access might be difficult if those mounts are rusty. I found a way around that, which will be discussed in a future episode.

The completion of these repairs meant I could turn to fitting the passenger side trunk panel. Episode three will cover this part of the trunk repair, the actual installation of all three trunk panels and their braces.