Plastic bumpers are a common component on most modern vehicles. They are designed to absorb minor impacts without damage, protecting the body of the vehicle. However, major impacts can still cause cracks, scrapes, dents or holes in a plastic bumper. Repairing minor damage to a plastic bumper is often preferable to replacing the entire bumper, which can be expensive. With some basic tools and repair materials, plastic bumper damage can often be fixed successfully and made to look like new again.
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Assessing the Damage
The first step in repairing a damaged plastic bumper is to thoroughly assess the damage. Look for any cracks, holes, deep scratches or indentations in the bumper. Also check for any pieces that may have broken off or any deformation to the bumper’s shape. Running your hand along the bumper can help identify any uneven spots or damage.
Consider what may have caused the damage. Was it a minor parking lot scrape or a more major collision? Higher impact crashes can sometimes cause bumper damage that extends beneath the plastic surface, affecting brackets or other components. This type of damage requires more extensive repairs.
If the damage is minor and superficial, fixing it yourself is often possible. But for cracks or damage that has significantly altered the bumper’s shape or structure, professional auto body work may be preferable.
Cleaning the Bumper
Before beginning repairs, thoroughly clean the damaged bumper. This allows you to see the full extent of the damage and removes any dirt or debris that could interfere with repairs. Use soap and water to clean the bumper’s surface. For stubborn dirt, a degreaser or all-purpose cleaner may also help.
Be sure to rinse off all cleaner residue and dry the bumper completely. Wipe away any wax, grease or oil with alcohol. This helps the repair materials adhere properly. Avoid using cleaners that leave glossy residues.
Sand any damaged edges or scratches lightly with fine grit sandpaper. This roughens the surface to improve adhesion. Take care not to excessively grind away too much plastic.
Repairing Cracks and Holes
For small cracks, gouges or holes less than 2 inches long in the bumper, plastic filler can often be used to repair the damage. Automotive plastic filler comes in a two-part epoxy resin that mixes together to form a putty. Follow the product directions closely.
Once thoroughly mixed, apply the putty directly into any cracks or holes, pressing it in firmly using a putty knife. Apply extra putty, mounding it slightly above the surrounding surface. Allow sufficient time for the filler to fully cure, which may take up to 2-3 hours.
Once cured, sand the putty using 100-150 grit sandpaper until it’s level with the surrounding plastic. Be careful not to sand away too much. Wipe away sanding dust and repeat repairs if any holes or cracks still show.
Apply primer to the sanded repair and lightly sand again. Then apply spray paint matched to your bumper’s color. Allow the paint to fully cure before handling the bumper. The repaired section can then be polished with compound and wax to blend with the bumper finish.
Using Epoxy for Larger Holes
For larger holes up to 4-5 inches long, fiberglass-reinforced epoxy can provide extra strength. Purchase a plastic repair epoxy kit. Cut fiberglass matting to overlap the damaged area by approximately 2 inches on all sides. Mix the epoxy resin and hardener together thoroughly following kit directions.
Coat the damage hole with epoxy, then lay the fiberglass matting over it, pressing it into the epoxy. Apply more epoxy over the matting, working it in until saturated. Allow to fully harden overnight before sanding smooth. Apply primer, paint and polish as with other repairs. The fiberglass reinforced epoxy creates a very durable repair.
Bumper Crack Stitching
Long cracks greater than 2 inches running across bumper sections can sometimes be successfully repaired using crack stitching. This involves drilling holes at each end of the crack then threading wire through the holes and pulling it tight to close the crack gap.
Start by drilling a 3/16 inch hole at one end of the crack, angling the drill slightly to penetrate the crack channel. Take care not to drill completely through the bumper. At the other end, drill another 3/16 inch hole in the same manner, intersecting the crack channel from the opposite direction.
Use 18 gauge steel wire and thread it through the two holes, running it through the crack. Pull the wire tight so the bumper sections draw together and the crack closes up. Twist the wire ends together to hold it tight. Apply epoxy over the twisted wire ends andalong the length of the crack using a putty knife. Allow the epoxy to harden fully.
Trim off any excess hardened epoxy and sand the area smooth. Then refinish with primer, paint and polish to blend. The tight wire stitching helps close the crack gap while the epoxy restores the bumper section and hardness.
Tab and Slot Repairs
Some bumpers have small tabs or slots that fit together sections for proper alignment. If these break or become damaged, bumper sections can sag or become misaligned. Repair broken tabs by thoroughly cleaning and roughening the surfaces where the tab connects.
Reattach the bumper section alignment by applying plastic-bonding epoxy to the tab and slot areas. Firmly press the components together for proper fit. Use masking tape to hold the section tightly together while the epoxy sets. Allow the epoxy to fully harden before removing the tape.
Smoothing Out Dents and Scrapes
For shallow dents, dings or surface scratches in the plastic bumper that have not cracked the surface, smoothing out the damaged area using heat may help improve appearance. Be very careful using this method to avoid burning or further damaging the bumper.
Heat can be applied using a professional heat gun, high heat hair dryer or even carefully with a halogen work light. Heat the dented or scratched area just enough to soften the plastic – around 250-400 degrees Fahrenheit. Avoid overheating.
Once the plastic is pliable, press the area firmly from the inside of the bumper using a body spoon or large putty knife to smooth it out. Continue heating and pressing until you achieve the desired shape. Allow to fully cool before refinishing. Be very cautious not to burn yourself or overheat the bumper.
Bumper Refinishing
After completing all bumper repairs, the area will need to be refinished for proper appearance. Thoroughly sand all repair areas, using 100-150 grit sandpaper. Sand just enough to rough up paint in the repaired section and blend it with the existing bumper finish.
Clean all sanding dust off the bumper and wipe with a tack cloth. Apply suitable primer to the repair area, covering approximately 2 inches beyond the repaired section to feather the edges. Allow primer to dry, then lightly sand again.
Spray on paint matched to your vehicle’s original bumper color, applying 2-3 coats. Allow paint to fully cure before handling. If needed, use compound and polish to smooth the newly painted repair area and blend with the bumper finish.
Be sure to apply fresh wax or sealant to the entire bumper to protect and restore luster. Take care not to wax or polish the non-textured section of the bumper, as this can make it more prone to scuffing. Your damaged bumper should now be successfully repaired.
When to Replace a Bumper
While many minor damages to bumpers can be successfully repaired through the methods described, more extensive damage often requires complete bumper replacement. Here are some situations where bumper replacement may be preferable to attempting repair:
– Cracks wider than 1/4 inch across large portions of the bumper
– Holes larger than 4 inches or multiple holes very close together
– Sections of the bumper missing, broken off or detached
– Damage that extends beneath the bumper surface into structural components
– Significant deformation that prevents proper bumper fit and alignment
– Extensive cracking, gouges or scrape damage over more than 30% of the bumper
– Brittle, heat-damaged bumpers that cannot be adequately repaired
– Repair costs exceeding 50-75% of complete replacement cost
Consult a professional auto body technician if you are unsure whether your damaged bumper can be adequately repaired or needs replacement. While replacing a bumper is more costly, it may be the better option for severely damaged bumpers or those with underlying structural issues.
Bumper Repair Costs
Here are estimates of average costs for common bumper repairs:
| Bumper Repair Type | Average Cost Range |
| Plastic welding small crack | $50 – $200 |
| Plastic filler for minor holes/scratches | $100 – $250 |
| Fiberglass epoxy large hole repair | $150 – $400 |
| Bumper section realignment | $100 – $350 |
| Dent/scrape smoothing | $50 – $150 |
| Full bumper refinishing | $200 – $600 |
| Full bumper replacement | $600 – $1500+ |
Keep in mind these are general estimates only and costs for professional repairs may vary depending on labor rates, needed materials, vehicle make and model. Minor repairs you perform yourself can result in significant cost savings.
Tips for Avoiding Bumper Damage
While bumpers are designed to absorb and resist damage, taking some preventative steps can help reduce the likelihood of needing bumper repairs:
– Drive carefully and avoid collisions, especially at higher speeds
– Park away from other vehicles that could open doors into your bumper
– Inspect your bumper regularly and touch up any minor scrapes before they spread
– Consider applying protective clear bra wraps or bumper trim guards
– Adjust your driving position, mirrors, etc. to improve visibility
– In low speed parking situations, brake early and pull in straight rather than risk sharp turns
– Install foam blocks/risers to prevent bumper damage when parking on steep inclines
– Choose a full-size spare if your vehicle has a compact spare, which can damage bumper height
– Walk around and inspect your bumper after parking to check for any new scrapes or damage
Practice defensive driving habits, be alert for pedestrians and obstacles, and take steps to prevent parking lot bumper scrapes. Addressing damage quickly can often let you repair minor issues before they worsen or require bumper replacement.
Conclusion
Repairing minor damage to your plastic bumper can restore its appearance while saving the cost of full replacement. Carefully assess the damage and use the appropriate method for the type and extent of damage your bumper has incurred. With some basic tools and repair materials, cracks, holes, deformations and surface scratches can often be fixed successfully. However, severely damaged bumpers may need professional repair or replacement. Take preventative steps to avoid parking lot bumps and reduce the likelihood of bumper damage occurring. Address any minor scrapes or flaws right away before they spread and cause more costly repairs. With proper care and timely repairs, the life of your vehicle’s bumpers can be significantly extended.