DIY Bumper Repair

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Introduction: DIY Bumper Repair

A nasty surprise greeted me when I went by to pick up my car up after some minor mechanical repairs I had done about a month ago. My car had been left parked out behind the shop for me, just out of sight., where someone turning around, had clearly run smack dab into my back bumper and left without a word...

Apparently this happens more frequently than I realized, but it has never happened to me before! Since the place to get an insurance claim estimate done was only a few buildings away, I drove directly there to have the damage repair assessed. A couple of days later, the estimate arrived to the tune of $1433! They were pretty much cosmetic repairs as far as i could tell (complete bumper replacement because of the dent and repainting of the entire backdoor because of scratches) - nothing that would really affect the safety or function of the car. This seemed like an unnecessarily expensive repair to me.

After pondering this over for a few days, and looking at ideas online for reforming the hull of a warped kayak, I decided to see if I could fix, or at least improve the bumper myself! Here is my 20 min ($1433) repair.

Step 1: Equipment and Materials:

  • kettle (boiling water)
  • insulated rubber gloves (optional)
  • hair dryer (extension cord long enough to reach your car)
  • towel
  • baseball bat (optional)
  • various sized pieces of scrap lumber
  • rubber mallet
  • assistant (to hold hairdryer)
  • nail polish (optional for scratches)

Step 2: Warming Up the Bumper

Plug in your hair dryer with the extension cord to get it in close proximity to the car bumper, but safely out of the way of the kettle and the water!

Have a good look under the bumper to plan the best access to the back of the dent where you need to apply pressure with the bat and other pieces of wood you have gathered.

You are now ready to get to work on warming up the plastic to make it soft enough to be reshaped.

Boil a full kettle of water (you will likely need to go and refill the kettle a few times).

Lay the towel over the area that you want to work on and gradually pour the boiling water on the towel being sure to keep your hands out of the way. If you have insulated rubber gloves, this would be a good time to use them, since BOILING WATER IS BOILING HOT! The towel helps the hot water stay in contact with the bumper longer and heat it through.

Gradually apply two full kettles of water like this and when the towel seemed to be losing its heat but is still quite warm, remove the towel so that you can see what you are doing and have your 'assistant' turn the hair dryer on hot and hold it close, but not too close, to the area to keep the plastic warm, while moving the hair dryer around at all times to avoid overheating the plastic in any one spot.

Step 3: Reshaping the Bumper

Move quickly while the bumper is warm and begin to apply pressure on the back edge of the dent with the rounded end of the baseball bat, especially working the sharp edges of the crease hard by moving the end of the bat back and forth across the creased area. As I worked the area, I could see the dent gradually getting smaller.

When it seems like the bumper is cooling off and hardening up a bit, stop and repeat the steps to throughly warm the bumper up again - pour another kettle or two full of boiling water over the towel and continue to do this, alternating between the boiling water and hair dryer over the next 20 minutes as needed...

This was pretty much how i did it. There was no grand big pop, it was a gradual process, of keeping the bumper warm enough to work and working the dent out by strategically applying pressure from behind.

Note: I started with the baseball bat since it had a nice rounded end, but at times found it was too long or too big to apply pressure in the right place at the right angle, so I moved between the various lengths of wood and the bat. I also found it helped to apply pressure at awkward angles by hitting a mallet against an intentionally placed piece of angled wood (photo 2).

In the end, I worked with which ever piece of wood i could fit into the small access space i had available to reach the underside of the bumper in the area i was trying to work, until I was satisfied.

Step 4: Back to New (almost!)

It is not perfect, but I was very happy with the results! Obviously, it makes it much easier to do a repair like this on a hot and sunny day :).

As an aside, I also cleaned up the the scratch in the tailgate with rubbing alcohol and when dry, applied a beautiful contrasting shade of sparkly turquoise nail polish, to protect the metal exposed by the scratch.

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    30 Discussions

    don't quit your day job ;-)

    Worked a treat thanks. I love my 100% electric Nissan Leaf but it has huge, expensive bumps and I hit a deer a while back. Deer was fine, bumper was not. Considering the size of the dent, the result is excellent. Didn't even need the hairdryer!

    I had this problem in Florida. I let the car set in the sun all day. Then i worked at the dent as you did from the underside with a handle from a plunger. Pored hot water on the dent. It poped out. Emedatatly poured Cold water on it to set the plastic. It kept the original shape.

    0
    user
    JRvZ

    1 year ago

    Nice car. Mine has the same dents so I will try this.

    0
    user
    JRvZ

    1 year ago

    Nice car!

    0
    user
    JRvZ

    1 year ago

    Yes Pallet M & too hot will not work well & may result in a hole in your bumper.

    If you carefully heat the plastic by moving your hair dryer or heat gun around, you can get the plastic hot enough that it takes very little effort to cause the dent to pop out. You should not need to force the plastic back into shape. I've done this twice and the second time, I used more heat and the result was much easier. No need for wood to pry the plastic. Just a push with gloved or double gloved fingers.

    I have done this on my VW Transporter to.

    But I had to remove the entire rear bumper in order to have access to the corner. The bumper is attached by plastic 'pop' nails (I don't know the right name in English, sorry) and a few Philips screws. The rear lights need to be dismantled too. It took me about 1 hour to do the job!

    No hot water, just an electric hot air paint remover, an Allen key, a screwdriver and the internet...

    ABS plastic has a kind of memory so it can 'return' to it's original shape...

    "IF" you have access to the inside of the bumper area, place a small deflated dollar store kids ball behind the damage area. Inflate the ball with a hand pump slowly. Use a heat gun carefully on the outside to soften the plastic bumper. Keep inflating little by little. In a short period of time, the crushed area looks nearly new. check out Youtube on how to color match and repaint/color-stain the plastic bumper again. Nice write up on this instructable too.

    My son's forester HAD the same issue, fixed it 2 months ago, similar method!

    I have done this simple repair a few times. I use a Harbor Freight heat gun Item #96289. You just need to be careful not to overheat the plastic. This way you do not need to worry about boiling hot water.

    You can also use chocolate... it has 546 calories º-º

    Thanks for showing me how to repair the back-up damage to my car!

    1 reply
    0
    user
    jrmont

    1 year ago

    Congrats on doing it yourself. When I see damage like this, I am often tempted to suggest to the owner how easy it is to DIY. In the case of my 4 week old Accord, the repair looks absolutely as good as new. No need to heat it in that case. When there is room behind the dent, a small inflatable play ball can be deflated and inflated to push from the inside.