How to Repair a Broken Car Bumper?
4 Answers
Car bumpers are mostly made of polypropylene plastic and are primarily located at the front (front bumper) and rear (rear bumper) of the vehicle. The repair methods for a broken bumper are as follows: 1. First, open the hood and observe how to remove the bumper. The removal method can vary depending on the car model, so it's advisable to look it up. 2. Align the cracks on the bumper and secure them with transparent tape to prevent deformation of both sides during the repair process. 3. Plug in the prepared soldering iron and flip the bumper over to inspect the cracks on the inside. Wait for the soldering iron to heat up, then use it to melt and fix the internal cracks of the bumper. Operate along the direction of the cracks. 4. Use a plastic welding gun (hot air gun) to weld along the cracks with the prepared welding rod. Remove the transparent tape used earlier and also use the soldering iron to trace along the cracks. 5. Next, use coarse sandpaper to smooth the areas treated with the soldering iron and those that need repainting. Once smoothed, apply putty and let it dry. Then, use wet sandpaper, starting with coarse grit and finishing with fine grit for a smooth surface. Rinse with water, dry with a clean cloth, and wait for it to dry completely before painting. 6. Before spraying paint, shake the spray paint well. Maintain a distance of about 20 cm from the surface, avoiding direct spraying. Maintain a slight angle and allow about 15 minutes between each coat, applying 5-6 layers in total. After the color paint, apply a clear coat to enhance the gloss of the vehicle's paint. If not done properly, the finish may lack shine, develop wavy lines, horizontal streaks, or bubbles. Let it dry for a few hours before reinstalling the bumper front panel. This will effectively repair the cracks.
Last time I reversed and cracked the bumper, I drove straight to my trusted repair shop. The mechanic inspected it and said the crack wasn't too long, so it could be fixed with plastic welding. They first cleaned the area around the crack, softened the plastic with a heat gun, and then used professional welding rods to fuse the crack together. After the repair, they sanded it smooth, sprayed it with the original factory paint code, and finally baked it dry. The whole process took three hours, and you can hardly tell there was any damage if you don't look closely. This kind of repair is suitable for small cracks and costs half as much as replacing the entire bumper. However, the mechanic reminded me that if the bumper clips are broken or severely deformed, the only option is to replace it.
My neighbor just used plastic steel putty to repair a cracked bumper. First, clean the dust from the broken surface, then knead the two types of plastic steel putty (A and B) into a clay-like consistency in the correct proportion. Quickly fill the crack and smooth it out. It will cure in three hours and can then be sanded and painted. The key is to buy high-temperature-resistant automotive-grade plastic steel putty, as regular putty will soften in the summer heat. This method is a temporary fix and not resistant to secondary impacts, making it suitable for those on a tight budget. After completing the repair, he drives very carefully to avoid bumps, fearing that the patch might come loose.
My friend's car got rear-ended and the bumper cracked into three pieces. The 4S shop recommended a replacement. An OEM pre-painted bumper costs over 2000 RMB, while an aftermarket one is around 600. During installation, they had to remove the headlights and wheel arch liners, and realign the radar mounting holes. They used professional tools to adjust the gap between the bumper and fender to ensure the doors wouldn't get stuck when closing. The whole process took six hours, and even the clips were replaced with new ones. The owner of the modification shop said that for cars over five years old with severely aged clips, it's safer to just replace the entire bumper.
