What Are the Causes of Rear Bumper Cracking?
3 Answers
Here are specific introductions to avoid bumper cracking: Summer: In summer, car bumpers are prone to automatic cracking. Cracking can only be resolved by replacement at a maintenance shop. Daily Precautions: Pay special attention during car washing. Although the outer paint is wrapped with stainless steel components, it is still susceptible to damage from wind, frost, rain, and snow. It is best to handle it appropriately during the car washing process by using alkaline reagents to wipe the bumper to prevent rusting, which is an important method to mitigate bumper cracking. Weather Impact: Affected by weather, internal rusting leads to quality degradation, which can induce cracking. Avoid driving through puddles or areas with intense sunlight during regular driving.
Last time my rear bumper cracked was because I was too hasty while parking and scraped against a concrete pillar while reversing—there was a loud bang and a crack appeared. Plastic parts are most vulnerable to sudden impacts, especially in cold winter temperatures when they become more brittle and can break with just a slight touch. Long-term exposure to sun and rain outdoors also makes plastic age and become brittle. Once, when I touched the bumper of my old car, it felt as crispy as a biscuit. Modified cars require extra attention—a friend’s car had a body kit installed, but the seams weren’t properly handled, and it cracked on its own after bouncing around on the road. Regularly checking if the mounting clips are loose is also crucial. I usually press the bumper a few times while washing the car—if there’s any unusual noise, it’s time for repairs.
After ten years of driving my old car, the bumper suddenly cracked. The mechanic said plastic materials naturally degrade over time. Prolonged exposure to UV rays makes the plastic's molecular structure brittle, and parking outdoors in sub-zero temperatures is even riskier—like in our northern winters, where washing the car and then letting it freeze can cause micro-cracks. If the car has been rear-ended before, extra caution is needed. During repairs, if the clips weren't installed properly or aftermarket parts were used, prolonged bumps can cause internal cracking. I make it a habit to apply silicone-based conditioner to the bumper before winter to slow down aging, and I avoid overloading the trunk to reduce stress.
