Rear Bumper Bracket: Service and Repair

Rear Bumper Impact Bar Replacement

Special Tools
J 42058 Frame Adapter Clamp
Removal Procedure

Warning:Refer to Approved Equipment for Collision Repair Warning .

1.Disable the SIR system. Refer to SIR Disabling and Enabling .

2.Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .

3.Remove all related panels and components.





4.Remove or reposition the wiring to avoid damage.

5.Repair as much of the damage as possible to the factory specifications.

6.Use J 42058 to secure the vehicle if pulling and straightening are required.





7.Locate the area inside the rear tub (1) over the top welds of the rear bar.





8.Cut out an access hole (1) over the top welds of the rear bar.

9.Save the cut-out piece to patch the hole.

10.Note the location and remove the sealers and anti-corrosion materials from the repair area. Refer to Anti-Corrosion Treatment and Repair .





Note:Do not cut into the frame rails.

11.Cut the welds around the perimeter of the frame rail ends. Cut the welds favoring the impact bar side of the joint.





12.Using a heat gun, detach the adhesive from the rear bar (1) to the rear compartment panel.

13.Remove the damaged impact bar.





14.Extract pieces of the impact bar which are left attached to the rail ends.

15.Straighten and deburr the rail ends. Keep the perimeter and shape of the rail ends as original as possible.

Installation Procedure

1.Temporarily position the impact bar for proper fit and alignment.





2.Clean and prepare all of the welded surfaces.

3.Apply GM-approved weld-thru coating or equivalent as necessary to the inside of the rail ends. Refer to Anti-Corrosion Treatment and Repair .

4.Position the bumper impact bar to the vehicle using 3-dimensional measuring equipment. Clamp the impact bar into place.





Note:If no trace of the original welds are present, follow the pattern specified for welding the side rails to the impact bar.

5.Using a metal inset gas (MIG) welder, stitch weld the rear bar to the frame rail ends.

Note:Do NOT top coat the bonding surface of the rear bar. Use primer only on bonding surfaces. Refer to the adhesive manufacturer's recommendations.

6.Clean and prepare all bonding and mating surfaces according to the adhesive manufacturer's recommendations.





7.Apply a consistent bead of structural adhesive to the top impact bar (1) to bond the rear compartment panel. Refer to Sheet Molded Compound (SMC) Panel Bonding .

8.Apply the sealers and anti-corrosion materials to the repair area. Refer to Anti-Corrosion Treatment and Repair .

9.Use the original cut-out piece to patch the access hole.





10.Apply adhesive bonding material as necessary to the repair area of the floor and the patch. Refer to Sheet Molded Compound (SMC) Panel Bonding .

11.Position the patch and press firmly into place.

Note:A leak proof seal is necessary so that exhaust and fuel fumes cannot enter the vehicle.

12.Smooth out the adhesive around the repaired area.

13.Verify that no voids or gaps occur in the adhesive.

14.Paint the repair area. Refer to Paint Identification Paint Identification .

15.Install all related panels and components.

16.Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .

17.Enable SIR system. Refer to SIR Disabling and Enabling .