Mustang Roush Upper Grille (2013-2014) Installation Instructions

Tools Required:
  • Phillips Head Screw Driver
  • Flat Head Screw Driver
  • 1/4-inch Ratchet or Handle
  • Razor Knife
  • Flat Head Screw Driver
  • Pliers
  • Metric Measuring Tape/Ruler
  • Denatured Alcohol
Install Difficulty:
  • Moderate
  • Moderate Project
1. To start installing your new Mustang Roush 421392 Upper Grille, open the hood then remove the radiator shield. Remove the eight retaining pins by prying the center pin from the expanding base using a flat head screw driver. The expanding base will now pry out of the opening easily. Set the pins aside in a safe place so you do not lose them.
Mustang Roush Upper Grille Install Image
2. Under the Mustang radiator cover there are four Phillips head style retaining pins. These are meant to be screwed out of their expanding base, but sometimes the edge must be lifted while unscrewing since the threads do not grab as intended.
Mustang Roush Upper Grille Install Image
3. There are four 8mm silver colored bolts in line with the above retaining pins that must be removed.
Mustang Roush Upper Grille Install Image
4. Turn the steering wheel fully to one side with ignition turned to the 'on' position, then turn ignition to off position and remove the key to lock the wheel. This will give access to one of the wheel wells where three 7mm bolts must be removed.
Mustang Roush Upper Grille Install Image
5. Pull the edge of the bumper at the corner next to the wheel well. There are three tabs that will pop loose. Turn the steering wheel the opposite direction and repeat on the other side.
Mustang Roush Upper Grille Install Image
6. Lying on the ground, face up, under the front of the car, remove the eleven 7mm bolts holding the Mustang lower air deflector in place.
Mustang Roush Upper Grille Install Image
7. The bumper will now be free from the car. Lay a towel down then carefully lift the bumper from the center front and lay it down directly onto the towel underneath. Disconnect the air temperature sensor by pulling it from the mount.
Mustang Roush Upper Grille Install Image
8. Disconnect the side marker lights by squeezing the grey connector and gently pulling it free.
Mustang Roush Upper Grille Install Image
9. Disconnect the Mustang fog lights (lowers shown) by gently pulling the tabs on each side of the connector just enough to release the connection.
Mustang Roush Upper Grille Install Image
10. The bumper with the old grilles attached is now fully detached.
Mustang Roush Upper Grille Install Image
Mustang Roush Upper Grille Install Image
11. Remove both Mustang grilles from the bumper by bending the retaining tabs slightly with a flat head screw driver and pressing the tabs out. There are fourteen on the upper and twelve on the lower grille.
Mustang Roush Upper Grille Install Image
Mustang Roush Upper Grille Install Image
Mustang Roush Upper Grille Install Image
Mustang Roush Upper Grille Install Image
12. The eight tab slots which look like the ones below must be cut using a razor knife as shown removing the inner lip. Be careful not too take too much off, a straight line across or less is best. Cut slowly and controlled to avoid slipping and cutting unintended areas of the plastic (or yourself!).
Mustang Roush Upper Grille Install Image
Mustang Roush Upper Grille Install Image
13. The center slot on the lower part of the grille opening must also be altered. Measure 10mm or .4" from the bottom of the existing slot and make a line with a marker. First cut up from the opening along the vertical edges. Next, score the plastic carefully in a straight horizontal line along your marker line. Once scored half way through the plastic use pliers to snap off. Clean up your edges with the razor if you wish, thought that is not required.
Mustang Roush Upper Grille Install Image
Mustang Roush Upper Grille Install Image
14. Apply the adhesion promoter supplied to the lower and upper edge of the Mustang lower grille (as shown below). The pad dries quickly, so apply immediately after removing from the foil packet.
Mustang Roush Upper Grille Install Image
15. Peel half of the clear backing from one of the two supplied double sided tape strips. Start pressing the tape to the outer upper and lower edges of the Roush grille (as shown below), working toward the middle. Once at the middle, pull the remaining backing off and finish applying the the remaining edge. Press the tape on securely. Repeat on the other side of the grille with the second tape strip.
Mustang Roush Upper Grille Install Image
16. Clean the inside area of the grille opening on the bumper with denatured alcohol for good adhesion. Place the lower grille into the opening with the red tape backing still applied. Bend the loose edge of the backing pointing out so you can access it to remove it after the grille is secured with the clips. Push the grille from the front with one hand while pushing the retaining clips tightly onto the tabs on the back side.
Mustang Roush Upper Grille Install Image
Mustang Roush Upper Grille Install Image
17. Pull the red backing from the tape strip and firmly press the Mustang lower grille edges to secure it to the bumper.
18. Remove the inner grille from the frame by slightly lifting the tabs (as shown below).
Mustang Roush Upper Grille Install Image
19. The two tabs openings on each outer side must be modified, since the replacement grille tab braces will hit the frame preventing the tabs from seating. Carefully press downward with a razor creating a 1/4-inch deep cut in line with the lip above (as shown below). Score between the two cuts until half way through the plastic, and then snap off the plastic with pliers. Clean up the edges with the razor.
Mustang Roush Upper Grille Install Image
20. Place the upper grille into the frame and press the U-clips onto the tabs snugly. Do not place the clips onto the tabs first and then attempt to push through the opening.
Mustang Roush Upper Grille Install Image
Mustang Roush Upper Grille Install Image
21. Place the upper grille attached to the frame into the grille opening and press into place making sure all of the tabs lock securely. You've now completed the installation of both Mustang grilles onto the bumper assembly.
Mustang Roush Upper Grille Install Image
22. Reverse the bumper removal procedure to reinstall and your Mustang Roush Upper Grille is now completely installed.
Mustang Roush Upper Grille Install Image