How to Install BMR Upper & Lower Torque Box Reinforcement Braces (79-04 All) on your Ford Mustang

NOTE: Reinforcement plates are supplied bare to give the option of welding the plates in. If you don't plan to weld the plates, paint the plates before installing with a rust preventative paint. 

Installation:

1. Remove rear seat by pulling the front of the seat upward. Remove upper section of rear seat.

2. Lift rear of vehicle and position jackstands under the frame rails. Allow the rear end to hang and support with jack.

3. Using 18mm socket and wrench, remove upper control arm bolts from chassis.

4. Using 1/2" drill bit, drill upward through the factory hole in the upper torque box through the floor pan as shown in IMAGE 1. NOTE: Holes need to be drilled as straight upward as possible.

5. Position lower reinforcement plate as shown in IMAGE 2 and install the two 1/2" bolts. 

6. From inside the vehicle, position the upper reinfocement plate as shown in IMAGE 3 and install the angled spacers, followed by the 1/2" washer and 1/2 lock nut. 

7. Using the lower reinforcement plate as a template, drill two 3/8" holes and install two 3/8" bolts as shown in IMAGE 4.

8. Install 3/8" washers and 3/8" lock nuts as shown in IMAGE 5. 

9. If welding, weld areas shown in IMAGE 6 and paint both plates and weld area with rust preventative paint as shown in IMAGE 7.

10. Reinstall upper control arm bolts and back seat. 

NOTE: Reinforcement plates are supplied bare to give the option of welding the plates in. If you don't plan to weld the plates, paint the plates before installing with a rust preventative paint. 

Installation:

1. Remove rear seat by pulling the front of the seat upward.

2. Remove rear seat frame using an 18mm socket and T50 torx bit shown in IMAGE 1. NOTE: Seat frame may differ based on year of vehicle.  

3. Remove rubber floor plugs using flathead screwdriver. NOTE: Later models have ABS wiring routed through floor plug. Unplug the ABS harness as shown in IMAGE 2 and trim rubber plug to fit between upper and lower plate. 

4. Lift rear of vehicle and place on jack stands.

On 1994 models refer to steps 5 - 7.

5. On later model vehicles, you may have to trim back material to allow the lower reinforcement plate to fit as shown in IMAGE 3 and 4. ​

6. Using a crescent wrench, pry the material back to allow the plate to fit as shown in IMAGES 5 and 6.

7. Remove two 8mm bolts holding e-brake and ABS harness as shown in IMAGE 7.

8. Using the 18mm socket and wrench (79-93) or 18mm socket and 21mm wrench (94-04), remove the nut from the lower control arm bolt but leave the bolt in place as shown in IMAGE 8.  

9. Position lower plate as shown in and bolt in place. Drill four 3/8" holes as shown in IMAGE 9. 

8. Place the upper plate in position as shown in IMAGE 10. (NOTE: If welding upper plates, mark the position of the plates and clean the area to be welded as shown in IMAGE 11.)

9. Using the 9/16" socket and wrench, bolt the upper plate in using the supplied hardware. 

If welding, continue to steps 10 - 12. NOTE: If welding plates, use caution not to melt wiring harness or grommet. 

10. Weld upper plate as shown in IMAGE 12.

11. Weld lower plate in the relief area as shown in IMAGE 13.

12. Mask off and paint plates and welded area.