UPPER QUARTER PANEL CRACKS INSTALLATION PROCEDURE

VEHICLES AFFECTED: 1984-85 "Y" CAR

This bulletin is being issued to announce the release of two new service parts for repair of cracked upper quarter panels: Rear upper body lower panel assemblies, (deft hand and right hand) P/N 10070219-20, and support brackets, P/N 14091061-62.

If a vehicle develops a crack in the rear upper panel (See Illustration 1) both the left hand affid right side brackets, P/N 14091061-2, should be installed and the cracked upper body lower panel should be replaced.

SERVICE PROCEDURE:

1. Disconnect negative (-) battery cable. 2. Remove rear tire/wheel assemblies. 3. Remove rear wheelhouse inner panel. 4. Remove rear facia. Refer to Corvette Service Manual, Section 2B-4. 5. Disconnect power antennae at rear, upper panel. (Left side panel replacement only). 6. Using cut-off wheel or die grinder cut a section of the rear roof panel away to gain access. (See Illustration 1). 7. Remove rear roof section by applying heat from heat gun and prying loose. Save this section for reinstallation. 8. Remove screws from sill plate at lock pillar and loosen load floor carpet to gain access to lock pillar access hole and insulator. (See Illustration 2). 9. Remove insulator, P/N 14065008, and ally other flammable material from the inside of the lock pillar. 10. Open rear hatch and remove weatherstrip trim molding weatherstrip from area of panel(s) to be replaced. 11. For either side replacement, remove complete outer skin by using heat gun and pressure, lifting skin away from inner structure. (See Illustration 3 for bond locations). 12. Remove all remaining adhesive by using heat gun and putty knife. 13. Fit and check alignment of new upper fear quarter panel, then drill two 1/8" diameter guide holes for sheet metal screws. (See Illustration 4). Remove screws and panel. 14. Remove underbody braces, P/N 14076557-8. (See Illustration 5). 15. Remove underbody plates, P/N l4O51179-80, (See Illustration 6). 16. Remove all excess bonding agent from the underside of the rear floor so that the brackets, P/N 14091061-2, fit flush on the underbody. (See Illustration 7). 17. Hand fit the bracket into position. (using grinder and hammer) Make sure that the bracket lays flush against both the frame and underbody. 18. With bracket hand held in place drill two rivet holes. (See Illustration 8) (use 1/8 diameter long shank rivet). 19. Clean and sand the bonding surfaces of the underbody and brackets. 20. Grind the area on the frame and bracket where the bracket will be welded on. 21. Apply epoxy adhesive (Dominion Sure Seal Rigid, Flex - XRF) to the top of the bracket. Use recommended epoxy. 22. Locate the two pop rivets (Reg. TM) and install. 23. MIG weld (ER70s-6 wire) the bracket to the frame at indicated locations, one weld at a time, allowing each weld to cool. (SEE illustration 9). 24. Clean, prime and paint the brackets. 25. Scuff the area on the new panets to be bonded. Then clean with wax and grease remover solvent. 26. Mix epoxy until uniform color with no streaks (use 1/2 pint of Rigid Flex part A and 1/2 pint of Rigid Flex part B per side). * See note for ordering epoxy. 27. Use plastic bag for application of epoxy. (large zip-lock (Reg. TM) bag is preferred). Put epoxy into bag and cut corner off to get a 3/8" diameter bead. 28. Apply bead to bond surfaces on vehicle. 29. Install upper quarter panel and fit. Insert alignment screws and clamp loosely where necessary to fit. Be sure front top corner of rear upper quarter panel is held below inner surface of outer roof panel. (See Illustration 10). 30. Let set for thirty (30) minutes. 31. Remove clamps and screws. 32. Use epoxy adhesive (Rigid Flex) to set in the roof panel section removed earlier. (See illustration 11). 33. V-groove and apply polyester filler. 34. Sand. 35. Prime and paint. 36. Mark and drill rear fascia holes. (See illustration 12). 37. Reverse tear down procedure.

MATERIALS:

Brackets, lock pillar to underbody (LH and RH) P/N 14091061-62 Panel assy., rear upper body lower (LH) P/N 10070219 Panel assy., rear upper body lower (RH) P/N 10070220

* Epoxy - Rigid Flex - XRF (refer to P.S.B. 86-2-158 dated September 15/86)

Available through: Dominion Sure Seal Inc. 5496 Gorvan Drive Mississauga, Ont. L4W 3E6

Phone: (416)625-7900 Telex: 06961303

DISCLAIMER

" We believe this source and their material to be reliable. There may be additional manufacturers of such material, General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms of for any such items which may be avallable from other sources."

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.