1979-1993 Fox Body Mustang Lock Set Install

How To Remove & Install 1979-1993 Fox Body Mustang Lock Set

If you're having issues locking and unlocking your Fox Body, this might be the right time to replace the lock sets. Today, we'll walk you through the removal and installation steps of our 1990 Fox Body Mustang.

Before removing the lock set, you'll need to remove the door panels from your Fox Body. We've set aside two different articles to remove 1981-1986 models and 1987-1993 models. Do this first before you begin.

Required Tools

• Rachet and Socket Set
• Rivet Gun W/ Rivets
• Metal Cutters
• Flat Head Screwdrivier
• Power Drill & Drill Bit Set
• Deadblow
• Plastic Pry Tool
• Sharpie or Marker
• Filer

1. With the door panel removed, look inside the door frame and locate the arm on the lock cylinder. Gently remove the rod from the arm and let it rest out of the way.



2. Use a pry tool and a microfiber towel to protect the paint, and work the lock cylinder retainer back and forth towards the rear of the door until it’s removed.



3. Push the cylinder away from the door from the inside and then remove it from the car. Go ahead and clean this area.



4. Locate the correct lock cylinder from the kit. Make a note of the arm direction on the cylinder and match the new cylinder to the old one.



5. Install the gasket over the cylinder with the lip side facing towards the bezel. Be sure to align the grooves in the gasket with the cylinder housing.



6. Position the new lock cylinder into place.



7. Push in on the cylinder and install the new retainer in the factory orientation.



8. If needed, fully seat the retainer with a small dead blow. Just be careful you don’t hit the surrounding area.



9. Reinstall the rod into the arm and check for operation.



10. You can reinstall the door panel and do the same for the other side.

1. Open either the hatch or trunk.



2. Drill out the factory rivet with a 1/8th inch drill bit. As you can see, the rivet was missing from this car.



3. Use the pry tool and microfiber towel again to dislodge the retainer.



4. Carefully depress the small tab on the retainer to fully remove it. On hatchback models, use a small flathead screwdriver and pass it through the rectangular opening where the retainer was.




5. Carefully pry against the lock cylinder to move back so you can grab it with your fingers and remove it from the car.



6. Coupe and convertibles will be a little different. Loosen and remove the three 7/16th bolts securing the latch and the lock cylinder bracket.



7. Maneuver the latch out of the trunk and disconnect the electrical connection if equipped.



8. Set the latch aside. There is another retainer securing the lock cylinder in place. Brace the face of the lock cylinder with your free hand and use a pry tool to work the retainer back and forth in an upward motion to dislodge it.




9. Remove it from the car, followed by the bracket.




10. For hatchbacks, use the existing rod as a template and place a mark on the new extension rod.




11. Cut it to length and then file it down.



12. For coupes and convertibles, make a note of the bend and the length.



13. Add a bend to the new extension rod, cut it to length, and file it down.



14. Since we’ll be reusing the exterior retainer, go ahead and file down the two shoulders on the new lock cylinder. This will allow the existing retainer to engage properly.



15. Test fit the lock cylinder and retainer and file down the shoulders more if needed.



16. Install the new rod into the new cylinder.



17. Install the gasket over the cylinder with the lip side facing towards the bezel. Be sure to align the grooves in the gasket with the cylinder housing.



18. On hatchbacks, install the new lock cylinder and verify that the rod passes through the plastic bushing in the latch.



19. For coupes and convertibles, install the new lock cylinder into the trunk.



20. Reinstall the bracket in the correct orientation, followed by the interior retainer.



21. Reposition the latch and reconnect the electrical connection if equipped.



22. Verify the rod passes through the plastic bushing.



23. Align the latch with the previous marks and tighten the bolts.



24. We chose to install a new retainer gasket from our site and reuse the factory retainer.



25. Fully seat the retainer.



26. Install a 3/32 retainer to secure the retainer.



27. Close the hatch or trunk and jump over to the glove box.

1. If you own a 1979 to 1986 Fox Mustang, you can skip this step since the included glove box lock cylinder will only work with 87 to 93 cars.




2. Loosen and remove the two 7mm screws securing the glove box door hinges to the dash.



3. Open the glove box door and remove it from the car.



4. On a workbench, loosen and remove the (6) Phillips head screws securing the door to the box.




5. Set the door face down and remove the (2) Phillips head screws securing the latch assembly.



6. With the latch in the “unlocked” position, rotate the latch until you can visually see the last tumbler.



7. Push this down with a small flathead screwdriver while pulling out on the cylinder.



8. Install the new glove box cylinder in the same orientation until it locks.



9. Check for operation and reinstall the door onto the box. Then you can reinstall the assembly back into the car. After that, you’re good to go!

Replacing the lock cylinders in a Fox Mustang is very straightforward. If you know us, then y’all know we enjoy the restoration aspect of fixing these cars, and this new lock cylinder set for our 1990 GT is another thing we can check off the list. Until next time, y'all know what to do for all things Fox Mustang; keep it right here with the real enthusiasts, LMR.com!