Mustang Dynacorn Quarter Panel Skin (1969) Installation Instructions

Tools Required:
  • Angle Grinder
  • Electric Drill
  • Spot Weld Cutter
  • Pneumatic Angle Die Grinder
  • Mig or Tig Welder
Install Difficulty:
  • Difficult
  • Difficult Project
1. To start installing your new Mustang Dynacorn 3647H Quarter Panel Skin, remove quarter panel extension. Then, with a wire wheel attached to your angle grinder, remove the paint on the quarter panel flange. This will make it easier to see the factory spot welds. Also, remove the rear quarter glass.
Mustang Dynacorn Quarter Panel Skin Install Image
2. Next, remove the paint on the leading edge of the quarter panel flange that wraps around the door pillar.
Mustang Dynacorn Quarter Panel Skin Install Image
3. Grind all of the corners and cut the panel just below the body line, above the Mustang rocker panel, and above the wheel housing. This will quickly get rid of most of the panel. Then go back and drill out all of the spot welds that are on the door pillar, wheel housing, taillight panel extension, and trunk drop off. There are also spot welds on the inside, where the rear window attaches the panel to the rocker panel.
Mustang Dynacorn Quarter Panel Skin Install Image
Mustang Dynacorn Quarter Panel Skin Install Image
4. Cut below the body line initially. This gives you a lip to hang the new Mustang quarter panel on, so that you can trace where the final cut needs to be.
Mustang Dynacorn Quarter Panel Skin Install Image
5. Hang the new panel on the lip that was left over in the previous step. Trace along the top of the panel with a marker to establish the cut line. Using a cut off wheel, cut the metal on the line. Hold the quarter panel up to the car and check fitment. You should leave a 1/16 inch gap for the butt joint weld between the new quarter panel and the old metal. This will help to ensure proper weld penetration.
Mustang Dynacorn Quarter Panel Skin Install Image
6. This is what the car looks like with the quarter panel removed. Inspect the inner structure of the car for any rust damage and repair if necessary. Remove any surface rust and apply a coat of paint on the structure to prevent further corrosion. Also, any surface where two pieces of metal will be overlapping should have a coating of Mustang weld thru primer applied.
Mustang Dynacorn Quarter Panel Skin Install Image
7. Using a pneumatic flanging/hole punch tool, punch holes along the leading edge and trailing edge flanges on the new quarter panel. It is also necessary to punch holes along the wheel housing lip, the bottom flange (were the quarter panel attaches to the rocker panel), and the bottom of the quarter panel where it attaches to the trunk drop off. These holes will allow the panel to be plug welded to the car. After punching the holes, remove the factory black coating from the backside of the flange and apply a coating of weld through primer. Note: Some newer Dynacorn panels are shipped from the manufacturer with weld through primer already applied. If your panel already has the primer applied, there is no need to apply more.
Mustang Dynacorn Quarter Panel Skin Install Image
Mustang Dynacorn Quarter Panel Skin Install Image
8. Once the new panel and the existing metal have been properly prepared, you may begin welding the panel to the car. Hang the panel on the car where it belongs and secure it in place. You can use clamps, if necessary, or have another person hold the panel while you begin welding. Begin by plug welding the leading edge flange to the door jamb.
Mustang Dynacorn Quarter Panel Skin Install Image
9. Next, move on to the wheel well. Plug weld the wheel arch to the wheel well. After welding the wheel arch in place, move on to weld the bottom of the panel to the trunk drop off, then weld the back of the panel to the taillight panel extension. As you are welding, repeatedly check the fitment of the panel to ensure that it hasn’t moved. The material on the wheel arch is a heat sink compound.
Mustang Dynacorn Quarter Panel Skin Install Image
10. This is a container of heat sink compound. This product absorbs excess heat that is caused by welding. Excess heat will warp sheet metal. Follow the manufacturer’s directions for applying this product.
Mustang Dynacorn Quarter Panel Skin Install Image
11. When welding in the panel, it is important to use stitch welds to keep warping to a minimum. Stitch welds will minimize the heat concentration. By using a combination of stitch welds and heat sink, the panel can be welded with no distortion. The picture below illustrates the combination of heat sink and stitch welds along the panel.
Mustang Dynacorn Quarter Panel Skin Install Image
12. In areas that are accessible, use a flat piece of copper as a backer when you are performing a weld. This will keep the weld from falling through the gap and will also act as a heat sink to prevent warping. The picture below illustrates how the copper bridges the gap between the two panels.
Mustang Dynacorn Quarter Panel Skin Install Image
13. Here is a view of the seam after it is welded.
Mustang Dynacorn Quarter Panel Skin Install Image
14. Here is another view of the completed weld.
Mustang Dynacorn Quarter Panel Skin Install Image
15. Now grind down all welds flush with the surface and finish with appropriate body filler.
16. The plug welds around the door jamb, taillight panel, wheel well, and along the bottom of the Mustang quarter panel (where it attaches to the trunk drop off) need to look like factory spot welds. This is first accomplished by grinding the plug welds flush with the surface, then filling in any minor irregularities with spot filler.
Mustang Dynacorn Quarter Panel Skin Install Image
17. Once the spot filler has dried, lightly sand smooth and apply a coat of Mustang etching primer to the area.
Mustang Dynacorn Quarter Panel Skin Install Image
18. Next, take a wooden pencil with a brand new eraser and press it into the wet primer. Twist the pencil as you pull it away.
Mustang Dynacorn Quarter Panel Skin Install Image
19. The pencil eraser leaves a blemish in the primer that resembles a factory spot weld mark.
Mustang Dynacorn Quarter Panel Skin Install Image
20. Here is another view of the finished mimicked spot welds. This view is of the passenger’s side, but the techniques are applicable for any area.
Mustang Dynacorn Quarter Panel Skin Install Image
21. Here is the final view of the Mustang Dynacorn Quarter Panel Skin installed.
Mustang Dynacorn Quarter Panel Skin Install Image