Ford 2003 Mustang Workshop Manual page 2453

4. Loosen the bolt until the piston stops against the tool.
5. Verify that the amount of piston travel on the dial indicator is within specification.
6. If piston travel is not within specification, select and install the correct servo piston assembly to
bring the servo piston travel within specification.
1. One groove
2. Two groove
3. Three groove
7. Remove the dial indicator and servo selection tool.