Early Mustang & Cougar cowl repair Okay, I m no expert but Bob suggested that I describe my experiences in replacing a rusty cowl in my 68 Mustang fastback I thought the cowl was good when I bought this Mustang, as I poured water down it and there were now leaks inside the car. Well a few years later and I m back to work on it and with some more examination I found out that it s not so good after all. Poking around with a screwdriver on the bottom of the lower cowl panel produced some small holes in it. Since the upper cowl panel is welded on the 65-68 Mustangs and 67-68 Cougars it s not really easy to repair, but with some work it is fixable. Since my Mustang is completely stripped to a bare shell it wasn t that big a deal like it would be with a nice running car. First off its not a small job, as the items to be removed include, the front fenders, windshield, heater box, rear fender apron to cowl extensions etc, but like I said with my car already stripped it wasn t that much more work to get at. The upper panel has to be removed and has a million (so it seems) spot welds in it. There are spot welds all around the perimeter of the upper cowl panel and another row at the top of the panel below the windshield molding. I started drilling spot welds with a special spot weld cutter - the common type with a removable cutting bit. It works pretty good on flat surfaces but not so good when the surface is uneven. I got about 2/3rds the weld cut when I started breaking the cutters and since I found out the upper cowl panel is now being reproduced I got mad and took the air chisel to the cowl side of the panel and got- er-done. Maybe one of the higher dollar spot-weld cutters that Eastwood Co. sells would be better to use, especially if you plan on trying to save and reuse your upper panel. At $150 plus shipping on the new panel it might be worth trying. Here is the upper panel I cut off. You can see the 2 rows of holes in the upper part of it. The upper holes are where it was welded to the back of the dash to make up the windshield frame and the holes just below it are where it was welded to the lower cowl panel.
Here is what it looks like with the upper panel removed. Notice the rusty lower panel. This was not one of Ford s better ideas and was before Quality is job 1 as from what I understand this lower panel didn t receive paint from the factory. This particular car was rust proofed when new so it did receive some coating which saved it for a long time but not forever. This closer view shows the rust holes that will wet your feet and carpet when it rains. Okay, I should have pointed out before now that you have 2 options at this time as how this is repaired properly; A left and right side repair panel that you weld in after cutting the bad sections out or a complete lower cowl panel. The two separate repair panels list for $49.95 each and the complete lower panel list for $174.95 from CJ Pony Parts. I chose to do the two repair panels for a couple of reasons. Yes, the cost is less, but my lower cowl was solid in the center and the complete lower panel is not drilled for the wiper mounting and seemed like more work in the long run. Once the upper panel is off the next step is to cut out the bad parts of the lower cowl panel. I marked out the cutout spots by measuring off the new replacement panels. I then ground through the spot-welds on the outer edges with a 4 ½ angle grinder followed by a 3 air powered cutoff wheel to cut the rest out. Since I had planned on doing a lot of sandblasting on the cars firewall, door jams and rockers this was the time to do it since the rest of the remaining lower cowl could be sandblasted clean. Here is the sandblasted firewall and the lower cowl with the removed bad parts.
If you notice the drivers side windshield wiper mount still in place that s because I had not yet decided if I wanted to remove that section. I did decide later to remove it and use the whole repair panel but made sure to measure the distance center to center from the pass side mounting to make sure all lined up properly later. I found it to be less work to drill the mounting points in the repair panel then to do all the extra fitting and welding required to save the original mount. This photo shows the 2 mounting locations of the upper cowl panel, the back of the dash and the top of the lower cowl panel. The picture on the left was taken before the whole sandblasting job was done. It was cleaned up more thoroughly the next day. Once it was all blasted I sprayed the bare areas with a self-etching primer (right picture). It s now time to fit and weld in the repair panels. Here the passenger side has been welded and the welds ground down. The driver s side has been fitted and clamped in place ready to be welded in.
Once the mounting spot for the windshield wiper was carefully measured and the center hole made with a hole saw, I cut out a section of the original panel and bolted it in place to use as a template to drill the 3, ¼ holes needed to mount the wiper. I then removed the template and bolted 3, ¼ bolts though the holes then welded the nuts to the panel. After all welding, grinding and cleaning was done I sprayed the whole lower panel with self-etching primer. Notice the nuts welded for windshield wiper mounting.
After several conversations with some local body men and some consultation from our own Jan Ove I decided that the new upper panel would be secured with a body panel adhesive instead of welding it back on. This will give me a better weather tight seal and has less 'after work'. (No grinding welds down later!) The lower panel then had all the attaching points ground down to smooth bare metal and then those areas were then masked off. It was then sealed with Dupont Velvaseal and then painted with semi gloss enamel. The new upper panel was then prepped in the same manner. Note the SEM adhesive gun used to apply the body panel adhesive. The new upper panel was test fitted beforehand and a couple of screws used to locate it onto the assembly. The next step was to actually glue the panel in place. The adhesive I used was a slow setting type that bought me time to get it all in place and clamped down. It was spread out with a acid brush to make sure all bare metal was covered for corrosion resistance. Plenty of clamps were used with care taken to not clamp down too tight as per manufactures recommendations.
Screws were used from the underside to clamp the lower panel to the upper panel where using clamps were not possible. This is an area that I was not comfortable in getting sealed up good if it were to be welded. I feel more comfortable that it s sealed up from the elements this way. The screws would be ground off from the topside later and body filler would be use over this area later. I let this set overnight then removed the clamps and ground down any adhesive that squished out. The rear fender apron extensions (new from CJ Pony parts, another hard to save when removing item) were then welded on and the upper clamp screws ground off and body filler applied. Well here it is, primed, sanded, ready to go AND non-leaking. I think that this is a very good place to use the body panel adhesives as it saves a lot of work plug welding and grinding all the welds down when you are through.