GM Service Manual Online
For 1990-2009 cars only

Repair Procedure

Important: Follow these guidelines when performing SMC repairs:

   • Clean scuff and solvent wipe all areas to be repaired.
   • For added strength and durability, cove and reinforce on at least one side of an SMC joint using a tacky mesh tape or equivalent.
   • When partial panel replacement is performed, use two inch backing plates made from SMC or E-coated steel, as a reinforcement for all butt joints.

  1. Scuff area where repair is to be performed.
  2. Clean bond area with lint-free rag using a water-based cleaner.
  3. For cracks,cove and reinforce on at least one side of an SMC joint using a tacky mesh tape or equivalent
  4. Sectioning joints require backing strips 50 mm (2 in) wide, which can be cut from leftover pieces of SMC.
  5. Apply a thin coat of Goodwrench Structural Bonding Epoxy (part number 12345726), or equivalent, to the entire join' area extending across the cut lines and across the backer.
  6. • Use tacky mesh tape or an equivalent reinforcement matting.
    • Allow to cure according to adhesive manufacturer's recommendations.
  7. Prepare the repair areas as necessary to resemble OEM appearance.

Bonding Procedure

Important: Use the following procedure when bonding undamaged SMC to epoxy-coated steel.

  1. Prime all bare metal areas with an anti-corrosion primer such as DuPont Automotive Finishes 1305S/1306S; Sherwin-Williams PSE 4600/PSH 4605, Martin-Sensor 5120/5123; and, R-M DE15, Glasurit 801-1552 or equivalent.
  2. • Some paint manufacturers recommend a pre-primer when bonding to epoxy.
    • Always refer to paint manufacturer's recommendations.
    • Do not combine paint systems.
  3. Clean bond area with a lint-free rag using a water-based cleaner.
  4. Scuff both surfaces to be bonded using a scuff pad such as 3M's Scotch-Brite "Red" scuff pad part number 07447 or equivalent.
  5. Ensure that the surface is clean and dry before applying adhesive.
  6. • Use compressed air.
    • Do not wipe surface with hand or rag.
  7. Determine whether adhesive is applied to the vehicle or the replacement panel. Refer to specific procedure of part being replaced.
  8. Apply a consistent adhesive bond to prepared surfaces.
  9. Mechanically retain panel in place to "wet out" adhesive along entire bonding surface.
  10. Allow to cure according to adhesive manufacturer's recommendations.