1. Clean the rocker panel with solvent and make sure the carpet isn't too thick to against the sill plate
2. Use a wooden hammer to hit the sills until it sits tightly
3. Stick the sills by the attached 3M tape on the rocker panel
4. Slightly knock the sills by hammer again and the sills should sit very tight on the panel
Advanced modification, replacing original material "plastic" to "aluminum"
Aluminum is flexible and stronger than plastic. To advance the part by changing plastic into aluminum, the part could last longer and it efficiently prevent the parts from being "cracked" easily.
We also have 68-71 type modification sills (OE#51471808680) in stock. PM us for more info!