The Damage

With the engine out and the engine bay pretty much stripped out, I was finally able to start evaluating what was really going on in there. From talking with the original owner, I knew there was a little collision damage at the front passenger corner side. I found that. And it's a rare vintage Mustang that doesn't have a rusted out battery tray - I found that too. The rusted apron overlaps from the previous post are also par for the course. I figured I'd just make a quick cursory exam of the dirty engine bay, and get started on replacing the battery tray and radiator support. Easy peasey.

Little did I know what horror was waiting for me in that engine bay...

 See, I even have my new parts ordered and hanging on the wall, ready for me to figure out how to install them!  (a good perspective shot of my work space. It's small, so I try to keep it clean.)

First, because you care, I'm going to show you around the front end of a vintage Mustang chassis. 

OK, so this is the inside of the engine bay, looking at the passenger side. Take a good look, we're going to spend a lot of time in here. Mustangs are uni-bodies, so this is structural metal as well. From far left to right, the vertical pieces of metal you can see the front apron (rusted from the battery), the shock tower (where the front suspension mounts and the engine mounts), and the rear apron (where the hood hinge mounts). 

All three of these pieces are mounted on top of the frame rail, which runs from the radiator support at the front of the car to underneath the firewall and floor as you move back. The diagonal piece is called a strut rod mount and it critical for wheel alignment and is welded to both the frame rail and the radiator support. The drivers side is basically a mirror image, but we'll spend our time on this side.

Let's look at what we have here on this particular automobile...

First up, the front apron. This is a top-down view. The battery sits here and inevitably leaks and rusts out the flat surface on the apron as seen here. Notice the gap on the right between the radiator support and the apron where you can see my jeans? That's not supposed to be there - that's collision damage.  No worries, both this apron and the radiator support are going to be replaced with shiny new parts that are hanging on the wall. I'm pumped! Let's do this!

Moving aft, looking top-down on the shock tower. Using a straightedge, I notice now that the protruding part facing up here (the engine mount) seems to be  bent a bit backwards. The drivers side does not look like this. This is...interesting...and a little troubling...

Moving aft again, now looking down on the rear apron. The hood hinge captive nuts are missing in 2 of 3 positions. No worries, I have one of these pieces as well. But look closely and you may notice (I can feel it too) that the apron is actually bowed inward towards the engine. How does that happen? Now I'm worried. The implication is that the piece has been compressed (collision damage?) and this is how it gave way. Not cool. Rust is one thing, but this is another kettle of fish altogether.  

Another view of the gap between the front apron and the radiator support. As I look closely, I can start to see where the parts have been beat back into position after a crunch. It's likely the crash had a lot more energy than I first thought, and that energy then moves through the whole side of the engine bay. Which brings us to...

...the Frame rail. This is 'the' strong arm in the front structure of the car. It's a foundational piece. And as I look at it here, I find a dent and a rough looking weld, circled in red. Tough to see this when the engine is in the way. Easy to see now.

The dent is evident next to a straightedge. This is not supposed to look like this. I also discover at this point evidence that a frame pulling machine was used on this frame rail at some point in the distant past and yet another welded repair on the outside of the frame rail at this same location, Ugh.

Moving back, where the frame rail is welded into the floor support, a piece that ties that frame rail to the floor. It's supposed to be a U-shaped tray that the frame rail sits in. With the engine removed, it's now obvious the floor support has a wrinkle in it - collision energy shoved the frame rail back and caused the support to bend.

And with the light shining just right, the outside of the floor support also shows a wrinkle. That's supposed to be a straight piece of metal.

So, after all of these discoveries, I cried, cursed the classic car deities, and had the car hauled off to a crusher - no reason to carry on, I'll just take up golf instead.

Just kidding. I had it towed down to a collision shop to get the frame checked out on a frame rack to get some professional measurements on my suspicions. Remember, I'm not the expert. Before I try to fix anything, I have to know where I starting. If this was just rust, it might not be needed, but for crash damage, absolutely.

Sure enough, the frame rack confirmed all my fears. Based on the chassis drawings from Ford, the frame rail was shoved back and down, and all the pieces touching it are in need of some sort of repair. Typically, you'd just pull it back into shape while on the frame rack. But the rail won't handle any more pulling due to the dents and the previous repairs. At a minimum, it has to go.

Advice from the shop - 

Replace the frame rail and the shock tower. The floor support is also bent, and both aprons are still shot. So this got much more complicated very quickly. The cost to have a shop do this work would be huge, likely thousands of dollars. I have a welder, and time, and I said I wanted to learn new skills...so I'm going to do the replacements.

My plan is to build a frame jig to hold the car while I take the old parts out and put new parts on. I need to design and build a custom frame jig, mount the car to it, then figure out how (and the order) of part replacement on the car, order parts, and learn how to reliably do structural plug welds that simulate the factory spot welds currently holding these pieces together. What have I gotten myself into? 

On the other hand, it's still better than golf. Let's get started.