Ford 2003 Mustang Workshop Manual page 180

12. Lower the front suspension lower arm and remove the jack stand.
13. Remove the spring.
1. Swing the front suspension lower arm out of the fender well.
2. Remove the spring and the spring insulator.
Installation
1. Install the spring.
1. Position the spring and spring insulator in the front suspension lower control arm.
2. Swing the arm into the fender well.