Depending on the year of manufacture, the mounting points may differ.

Front bumper

 

-open the hood.

-under the hood, pull out six pistons and remove the trim above the radiator grille.

-under the cover, release two pistons (you need to rotate 90 degrees) and Unscrew one screw that attaches the top of the radiator grille.

-release the retainers in the fenders under the headlights (you need to pry with a flat screwdriver) and remove the radiator grille.

-in the opening between the headlights, we Unscrew four screws (twisted from top to bottom).

-(if any) in the wheel arches, Unscrew the screws that attach the undercarriage (front part).

-Unscrew one screw on each side, which attaches the sides of the bumper to the brackets.

-remove the connectors from the fog lights.

-with an assistant, we pull the bumper forward.

Front bumper mounting diagram for GMC Sierra (1999-2007)

Front bumper mounting diagram for GMC Sierra (1999-2007)

Front bumper mounting diagram for GMC Sierra (1999-2007)

 

 

Rear bumper

 

-pull out the license plate lights and remove the connectors.

-from the bottom side, we Unscrew two nuts and two screws on each side, which attach the bumper brackets to the body.

-Unscrew the screws (screwed from the bottom up) that secure the lower part.

-with an assistant, we pull the bumper back.

Rear bumper mounting diagram for GMC Sierra (1999-2007)

Rear bumper mounting diagram for GMC Sierra (1999-2007)

Rear bumper mounting diagram for GMC Sierra (1999-2007)

 

How to remove front and rear bumper GMC Sierra (2007-2015)