The days of cutting, welding, and otherwise repairing rusty, old cowl panels are over. Well, at least for '67-'68 Mustang owners. Dynacorn International has released brand-new sheetmetal reproductions of the upper and lower cowl panels for '67-'68 Mustangs, which means you can trash the old leaky panels and replace them with Dynacorn's fresh sheetmetal, available from National Parts Depot.
Cowl-panel repair has been the bane of vintage Mustang owners for decades. Leaves, pine needles, and other trash can enter the cowl through the exterior vents and accumulate around the water dams at the corner vents inside. Rain water adds moisture to the inaccessible mess, resulting in rust, especially at the dams, which eventually allows water to enter the interior through the fresh-air vents. Many a Mustang owner has been surprised by wet carpet after a rainstorm or even a car wash.
Because the cowl panel is an enclosed assembly, repairs are difficult. Temporary repairs like plastic cowl-vent caps and fiberglass replacement dams have been available for years. More permanent repairs have meant cutting open the cowl panel to replace the dams and surrounding sheetmetal. According to Matt Simmons from Classic Creations of Central Florida, he can spend up to a week repairing a rusty original cowl.
Dynacorn's reproduction cowl...
Dynacorn's reproduction cowl panels for '67-'68 Mustangs are a welcome relief for Mustang owners with rusty, leaking cowls. All brackets are included, so there's no need to cut them out of the old panels for transfer to the new panels. When welded together, the upper and lower panels create a brand-new cowl-panel assembly.
Of course, even with completely new panels, the replacement is not a job for the typical weekend mechanic. Removing the original cowl requires removing fenders, cutting out spot welds to remove the old cowl panel, and welding the reproduction panels together before the final alignment and welding. You'll also have to paint the upper panel to match the car's exterior because the cowl forms the sheetmetal between the hood and windshield. It's a big job if you're performing a cowl-panel R&R on a complete car, but less time-consuming and labor-intensive if you do it during the course of a restoration.
As you've likely heard, Dynacorn is working on a complete '67 Mustang body, which explains why the '67-'68 cowl panels are available before '65-'66. According to National Parts Depot and confirmed by Classic Creations of Central Florida, Dynacorn's lower panel can be adapted to '65-'66 Mustangs, although the shape is not quite correct because it's made to clear the '67-'68 Mustang's underdash pedal support. However, that area is not visible when the panels are welded together as an assembly and installed.
1 To remove the old cowl-panel...
1 To remove the old cowl-panel assembly, the fenders must be removed and the original spot welds cut out. Here, Matt Simmons and Merv Rego from Classic Creations of Central Florida are removing the cowl from our subject vehicle, a '67 Mustang convertible. Merv points out that you'll need to support the car's frame underneath the cowl area, especially on convertibles, because otherwise only the firewall is supporting the car. Without support underneath, the car could sag in the middle.
2 With the old cowl panel...
2 With the old cowl panel flipped over, you can see the hidden rust damage. In fact, this cowl had been repaired previously, and even the repair sheetmetal was rusted through.
3 Before welding the upper...
3 Before welding the upper and lower panels together, they must be aligned to drill the holes needed for the spot welds. Matt secures the panels with clamps before drilling.
4 With the panels aligned...
4 With the panels aligned and secured together with clamps around the edges, drill small pilot holes through both panels around the edges.
5 Next, open up the pilot...
5 Next, open up the pilot holes to 38 inch. The final pattern should look something like this. The two large holes are part of the panel stampings, used for alignment purposes.
6 The holes along the top...
6 The holes along the top of the upper panel, where the panel will be welded underneath the windshield, can be made with a sheetmetal hole punch, which Matt says is available from tool companies for around $20.
7 Use a sander to remove...
7 Use a sander to remove the burrs from the freshly drilled holes.
8 For durability, it's a...
8 For durability, it's a good idea to apply a bead of sealer around the water dams before welding the panels together. This will provide extra protection from the moisture collected by leaves, pine needles, and other trash.
9 After scuffing in preparation,...
9 After scuffing in preparation, paint the inner panel surfaces body color because you will be able to see into the cowl through the upper vents.
10 After the paint dries,...
10 After the paint dries, remove the paint on the areas to be spot-welded.
11 Once again, clamp the...
11 Once again, clamp the upper and lower panels together in preparation for final welding.
12 Use a spot-welder to weld...
12 Use a spot-welder to weld the panels together at each drilled hole where the panels meet at the windshield area. Matt welds from underneath the top panel, which reduces the amount of final grinding and finish work, making for a cleaner appearance on the top panel.
13 Here's a good look at...
13 Here's a good look at Matt's spot-welds where the lower panel meets the upper panel at the windshield area.
14 Place the semi-welded...
14 Place the semi-welded cowl-panel assembly into place on the car body. It's a good idea to cover the vents with tape to prevent debris from accidentally falling in. Once the panels are welded together, you won't be able to access the interior area.
15 Use an awl to align the...
15 Use an awl to align the cowl panel to the body. There are holes, four in front and one at each side, in both the cowl panel and the body for this purpose. With the cowl aligned, clamp it into place before welding.
16 Now comes the tedious...
16 Now comes the tedious part: Spot-weld the cowl panel into place at all of the nearly 200 holes.
17 Before final welding,...
17 Before final welding, it's a good idea to lay the fenders into place to check the fit. It's easier to remove a few welds for adjustment now instead of having to cut out all the welds later.
As you see, the fender and...
As you see, the fender and cowl fit perfectly, so Matt continued with the welding to complete the installation. Both Matt and Merv from Classic Creations of Central Florida agreed that the Dynacorn reproduction cowl panel is a quality piece.