TSB 90-06-12 Floor Cracks at Seat Bases

ISSUE: Floor pans may crack near the seat track attachments on Bronco and F-Series Super Cab trucks equipped with captain chairs.

ACTION: Install floor pan reinforcements on the top side of the floor pan. Refer to the following procedure for service details.

SERVICE PROCEDURE

1. Remove both front seats and seat tracks. Refer to the 1989/90 F-Series/Bronco Shop Manual, Section 41-01 for service details.

2. Inspect the seat tracks for cracks. Replace any damaged tracks. Refer to the 1989/90 F-Series/Bronco Shop Manual, Section 41-01 for removal and installation information.

3. Remove the carpets/mats. Refer to the 1989/90 F-Series/Bronco Shop Manual for service details.

4. Inspect all eight seat track attachment nuts on the floor pan. Fusion weld any loose nuts to the floor pan.

5. Remove all sound insulation material from the floor pan in an area big enough so that the reinforcement does not contact any insulation.

6. Clean the floor pan surface with 3M General Purpose Adhesive Cleaner.

7. Inspect the top side of the floor pan for cracks.

8. Apply 3M joint and seam sealer on the top of each crack.

9. Remove the floor pan reinforcements from the service kit. Place them upside down on a work bench or table.

10. Clean the bottom surface of both reinforcements with 3M General Purpose Adhesive Cleaner.

NOTE: A 3M AUTOMIX APPLICATOR GUN CAN BE PURCHASED FROM YOUR LOCAL 3M SUPPLIER. THE APPLICATOR GUN IS REQUIRED TO APPLY THE 3M STRUCTURAL ADHESIVE.
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11. Apply 1/4"-3/8" (6.35-9.53 mm) beads of 3M Structural Adhesive to the bottom surface of both reinforcements.

NOTE: ADHESIVE HARDENS WITHIN 30 MINUTES. PERFORM STEPS 10 THROUGH 13 AS SOON AS POSSIBLE BEFORE ADHESIVE CURES.

12. Place the left hand reinforcement on top of the floor pan sheet metal on the driver's side.

13. Secure the reinforcement to the floor pan with the (4) seat track mounting bolts and (4) flat washers.

14. Place the right hand reinforcement on top of the floor pan sheet metal on the passenger's side.

15. Secure the reinforcement to the floor pan with the (4) seat track mounting bolts and (4) flat washers.
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16. Using the holes in the left hand reinforcement as a guide, drill six (6) 1/4" (6.35 mm) diameter holes through the reinforcement and floor pan in the locations shown.

a. Install one (1) pop rivet in each of the critical locator holes immediately after drilling the individual hole.

16.b. Drill the remaining twenty-seven (27) 1/4" diameter holes in the reinforcement and floor pan.

c. Install the remaining twenty-seven (27) pop rivets.

d. Remove the (4) seat track mounting bolts and flat washers.

17. Repeat the above procedure for the right hand reinforcement, if required.

18. Spray Super Seal on top of both reinforcements and about 1" (25.4 mm) beyond the edge of the reinforcements.

19. Replace the carpets/mats.

20. Replace both seats.

21. Raise the vehicle and spray Super Seal over the bottom side of the floor pan to cover all cracks and pop rivets.
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OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under Basic Warranty Coverage
OASIS CODES: 1051, 1200

List price on the LARGE reinforcements is ~$60 ea.
List price on the kit of 2 small plates is ~$31/kit.
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