Bumper Energy Absorbers, Crush Boxes, and Bumper Reinforcements
Let's go back to basics with the ever-popular front-end damage and what to do with the bumper energy absorber, crush boxes, and bumper reinforcement.
Bumper Energy Absorbers
First up is the bumper energy absorber. In general, bumper energy absorbers are designed to absorb minor collision energy by crushing or collapsing, thus reducing physical damage to the vehicle structure. Bumper energy absorbers are typically designed for one-time use and must be replaced if damaged.
If you are thinking, wait a minute doesn't GM say you can repairs some of them? You're most likely thinking of the GM repair bulletin for polypropylene energy absorbers that involved using a specific hot-melt glue (not your average crafting type). However, in 2007 GM released an update to the original bulletin (63-20-02) making that repair no longer acceptable and indicated that the previous bulletin should be discarded. Per the updated GM bulletin #07-08-63-001: "Because the energy absorbers are relatively low in cost to replace, it is now more cost efficient to replace the energy absorbers whenever they are damaged."
Let's move on to the bumper reinforcement. The bumper reinforcement is typically made from very strong materials such as UHSS or aluminum and its job is to distribute the collision energy and may affect timing of the SRS. Bumper reinforcements are typically replaced if damaged. Don't forget to inspect mounting points. Any cracking, tearing, or deformation of the bumper reinforcement, as well as any damage that may affect the crash characteristics of the vehicle, will require replacement of the part.
Here are a couple of OEM position statements that address bumper reinforcements:
Honda/Acura Unibody Repair Position Statement: "Because they are made of high strength steel, door and bumper reinforcements must not be repaired or straightened."
Toyota/Lexus/Scion CRIB #161: "Damaged bumper reinforcements require replacement."
Last but not least, the crush boxes. Crush boxes are designed to be sacrificial parts and should be replaced if damaged. Do not straighten a damaged crush box. Note that some bumper reinforcements are supplied with built-in crush boxes.
That wraps it up. You can also find the information from this article though your searches of the Ask I-CAR database on this site.
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