Passenger Toe Board

The "toe boards" are also known as the firewall to floor extensions. These are the angled panels where the driver and passenger feet reside between the floor and the firewall to the engine compartment. In the case of most of the vintage Mustangs that are in need of restoration, holes and rust develop in these areas as a normal state of wear, tear, and weathering.

In an original car, the toe boards are stamped as an integral part of the panel that makes up the firewall. Fortunately, patch panels are made available and I bought a pair several weeks ago and proceeded to primer them with PPG DP74LF primer to protect them.

This is the passenger side patch panel as it comes from NPD (after I applied primer):

Unfortunately for me, I seem to have purchased a set of panels for a coupe. Coupe panels don't have the cut-outs for the inner rockers at the outside corner. So, I searched several internet vintage mustang parts resellers and couldn't for the life of me find a panel made for a convertible. I finally gave up and opted to modify the coupe panels. In order to do this, I first had to cut out the inner rocker notch. The first step was to make a template out of some heavy poster board as shown here:

The template was then transferred to the patch panel:

I then drew tabs that I would use to weld the panel to the inner rocker.

I cut out the notch with my angle grinder. I soon discovered another problem with the coupe panels. There's a flange on the outside edge that faces down. This interferes with the torque box on a convertible:

The flange then had to be bent upwards in addition to bending the inner rocker notch tabs upwards as well:

With the patch panel laid out, it was time to mark a straight and consistent hole in the original toe boards into which I would weld the patch panel.

After a very long time and several iterations of fitting, measuring, and cutting, I finally had my finished toe board patch. I drilled plug weld holes for the two frame rail flanges and a pattern of 10 plug weld holes to attach to the torque box.

I first tack welded the panel into position and then butt welded the seam and filled the plug weld holes. One of the "joys" of this was that the indention on the right side of the panel, where I had drilled 4 of the plug weld holes, didn't meet the bottom of the similar indention on the torque box into which this indention was to lie. So, I had to hammer the living crap out of said indention to get the plug weld holes to come in contact with the friggen torque box. A little taste of hell which I didn't expect or need:

I then ground down the welds from both sides of the panel, filled many blow-outs and pinholes, ground again, rinse, wash, repeat. In total from beginning to end, this task took me about 3 days for a total time of around 8 straight hours of pain and suffering. I really have to wonder if maybe buying a complete firewall and patching in the entire bottom half would have been easier. One of the primary hassle's was squatting/kneeling under the dashboard area to complete all the steps. I'm really dreading repeating this on the driver's side but, hey, if it were easy... I'd be done by now.

Finishing LH Torque Boxes & Inner Rocker

After the inner rocker and front torque box are installed, I needed to reinstall the trunk vertical brace, the door reinforcement, and rear torque box cover as shown here:

... And then close up the the end of the inner rocker panel and tie it into the wheel well.

After welding comes grinding... lots of painful, boring, angry grinding.

Up front I patched the cowl side panel where it had rusted out and then ground and ground and ground some more.

A shot from below the front torque box showing... you guessed it... more grinding.

The good news is that the structural steel work is done and it's floors and body from here on out.

Welding LH Inner Rocker & Torque Box

After I test fitted the inner rocker and torque box as an assembly, I marked each for it's relative position against the outer rocker and front floor support. I removed them and then drilled umpteen-bazillion holes (okay, I'm exaggerating a little) along the top and bottom of the inner rocker every 2 inches as wells as in strategic locations around the torque box. The rear 1.5" feet or so of the top flange of the inner rocker had to be drilled instead of the outer rocker because of the inaccessibility of the upper flange due to the rear quarter panel and rear door support structures. I also drilled the outside edge of the bottom of the rear torque box to be welded up against the bottom of the inner rocker.

After having drilled all those holes, I reinstalled the panels into the car and clamped them back in place. I then marked each hole's position on the panel behind it with the tip of a sharpie as you can see from the front torque box area here:
... and along the outer rocker here:

I then removed the panels... again... and used a flat-end spot weld drill to expose bare metal under each sharpie dot to weld to. This is a royal pain compared to just spraying weld-through primer on and welding through it but my theory is that welding to bare metal splatters less and is easier to do than into weld-through primers and the bar metal is protected with PPG primer all the way up to the actual plug weld itself with no bare metal exposed between panels. Frankly, I don't trust weld-through primer to protect the metal as good as PPG primer and/or ZeroRust can. My Ford Weld & Sealant Assembly Manual called for weld-through primer between panels and look how well that worked out!

Here's a shot of the rear section of the inner rocker where it attaches to the rear torque box and outer rocker. This area required welds along the edges of the rear spring perch, the top flange of the inner rocker, and the outside edge of the rear torque box bottom where it contacts the bottom of the inner rocker. Note the color differences between PPG's DP74LF primer (the rocker panel), and ZeroRust Red Oxide (the other stuff).

Looking forward to the front torque box. Welds required along the torque box to inner rocker flanges, the cowl side panel, side and bottom of the floor support:

A seam weld was required along the frame rail with welds to the inner rocker end flange, the bottom outside section of the torque box to the bottom of the inner rocker, the bottom of the frame rail/floor support and, of course, all along the bottom and top of the outer rocker:

Inner Rocker Seat Belt Captive Nuts

Since I had the driver side inner rocker on the floor for drilling out plug weld holes, I decided it was a good time to mount captive nuts for 3-point seat belts that I intend to install. I asked the folks on the VMF for advice and was directed to several links of installs others had done. It seemed to me that the common requirement was a captive nut to be installed about 10" behind the existing front seat belt captive nut, just in front of the rear torque box.

So, I selected a location 10" behind the existing captive nut to drill the hole for the seat belt anchor plate that I bought from NPD. I drilled 2 holes, each 3/4" out from the mounting hole for plug welds.

I fished a wire through the mounting hole to the end of the rocker panel where I inserted a bolt through the captive nut on the bracket, wrapped the wire around the end of the bolt and pulled it through the hole in the rocker where I fastened a nut and washer after having marked center on the plate and across the holes.

I filled in the plug weld holes to fasten the plate to the inner rocker panel and dropped the bolt down and dumped it out the end of the rocker. Note, the bolt I used was not threaded into the bracket captive nut but was a smaller size that would easily fall out.

I repeated the process on the existing passenger side rocker as well. For this side, I had to open up the wheel well at the bottom to gain access to the inside of the rocker and reweld it.

Now I have additional mounting points for 3-point seat belts. I have yet to install the upper point at the rear of the door but that can wait until after the floor is in.

Update 5/16/2013: This mounting point worked well for retaining the retracting reel of a 3-point seat belt.  Please see Safety First - Shoulder Belts

Driver Side Inner Rocker/Torque Box Prep.

Before continuing on with the preparation of the driver's side structural members, I needed to weld in the driver side floor support that welds to the back, bottom of the front frame rail. This member is attached to the frame rail via 30 plug welds, each requiring a hole to be drilled. In case you don't remember from prior posts, a plug weld is where a piece of metal is drilled, mated against another piece of metal and then the two are welded together by filling the hole thus simulating a spot weld. In this case, there are 2 rows of 5 welds on each of the 3 contacted sides. In addition, there are 4 more welds to the sides and 2 to the top middle of the member where the floor cross member ties the two floor supports together.

The resulting part looks like swiss cheese:

I test-fitted the floor support to the frame rail, marked the hole locations, and then used a flat ended spot weld bit to expose a 3/8" circle of bare, clean metal to weld to as shown in the image below.

I then clamped the two parts together and systematically filled in the holes to bind the parts.

I could next move onto straightening, filling holes, and generally preparing the sheet metal around the area of the inner rocker where I wouln't have access after installing the inner rocker.

The area is doused with Ospho, rinsed, and scoured to neutralize the rust.

A view of the front portion of the inner rocker after cleanup.

Everything that harbored surface rust within the vicinity of the inner rocker was given a coat of ZeroRust encapsulator to seal it up in the event that moisture ever contacted the area in the future.

A view of the front portion of the outer rocker after ZeroRust is applied.

The driver's side of the car is now ready to install the torque box and inner rocker panels. This is a shot of an initial test fit. The torque box needs some adjustment as it doesn't fit quite perfectly. After I do that, it's time to weld and then the car will once again be structurally sound.