Complete Cowl Repair Procedures for '65-'68 Mustangs

23 The top half of our cowl had seen better days as well, with several rust holes along the front and sides of the cowl top. These would have to be repaired before welding the cowl top back into place.

24 Any areas that needed to be repaired were cut away until there was good metal to weld to, then custom patches were formed to repair the areas. We used scraps of good metal from what we trimmed off the cowl hat patches.

25 Here is but one of several custom repair patches that were made to our cowl top. Notice how well the new patch blends into the original cowl due to the butt-welding. Don't forget to drill or punch new holes for MIG-welding, if the patch is over an area to be welded.

26 After wire-wheeling the underside of the cowl top, POR-15 Metal Ready is brushed on to neutralize the rust. Notice that the upper corner of the cowl in this photo was practically rebuilt with custom patches.

27 The underside of the cowl top is then sealed with POR-15 black rust-preventive paint. When brushing on the POR-15 in either the cowl area or on the cowl top, make sure that you don't get any of the POR-15 paint on the areas that will actually be welded together. Use weld through primer in these areas.

28 Lay the top of the cowl assembly in place and use a large drift, a line-up bar, or a tapered punch through the factory alignment holes to set the top correctly. Double-check critical areas, such as wiper pivot holes, shock tower brace holes, and so on. Clamp the cowl top securely with several locking pliers to prevent movement.

29 The cowl top is MIG-welded back to the main cowl in several locations to hold it in place without the requirement of the locking pliers. At this point, the remaining spot welds that were drilled out are now welded closed again.

30 Break out the grinder again and clean up all the welds surrounding the cowl assembly. Ensure that the welds are strong and that you didn't miss any of the drilled spot welds.

31 New rear fender apron extensions are welded into place over the gap between the cowl and the rear fender apron. The price of the new extensions is reasonable and makes for a quicker, better-looking repair.

32 Before the cowl can be sealed with brush-on seam sealer, several coats of rust preventive primer must be applied. You should never brush seam sealer onto bare metal, because the seam sealer will trap moisture against the bare metal. Any quality, high-solids paint will work well for this.

33 Using a disposable acid brush is the quickest way to brush the seam sealer into all the little seams and welds. Start at the base of the windshield and work your way around the cowl. Don't forget to brush seam sealer under the fender apron extension as well.

34 When brushing the seam sealer across the front of the cowl, don't be afraid to apply a thick coat. The original factory sealer in this area was usually applied to the height of the lower cowl lip. Don't be too concerned about the shock tower brace mounting holes being covered with seam sealer--they can easily be found and the sealer can either be cut or dug out.