Mustang Accessory Sill Plate (1964-1968) Installation Instructions
1. To start installing your new Mustang accessory sill plate
, open the door (I did the drivers side first) and loosen the screws on the factory sill plate, about a half turn, so the heads will not stick up and scratch the bottom of the door.
2. Turn the accessory sill plate over and apply 3M trim adhesive
. I used a about a drop that was the size of a half a marble at six inch spacings.
3. Slip the Mustang sill plate
under the door sill and position it so it is even along the outer edge.
5. Repeat on the other side. For this side, I applied the adhesive spaced further apart and with a larger marble size amount. When the accessory sill plate was placed on the Mustang, I had to clean up some excess adhesive that came out when I tightened the screws on the Mustang sill plate
6. The next morning, I drilled 3/32” pilot holes for the Mustang accessory sill plate screws
, which will be placed through the door sill using the holes in the accessory sill plate as a guide. Be careful when you tighten these screws, as you don’t want to strip them out or over tighten.