How much does it cost to replace or repair a damaged windshield? | Measures and first aid methods | MOBY [モビー]

Estimated scratches and cracks that need to be replaced

© Aleksandr Lesik /

If the windshield needs to be replaced instead of repaired, it is in a state where there are scratches or cracks that correspond to the following.

  • The size of the scratch exceeds 2 cm (about 500 yen coin)
  • It is chipped or dented
  • The cracks are like a spider web
  • It is in a position that blocks the driver’s view.
  • It is within 10-20 cm from the top, bottom, left and right edges of the glass.
  • Near the defroster (a blower that removes cloudiness and condensation)

If the scratch is on the edge of the glass or near the defroster, it will be easily cracked by strong vibration or temperature change regardless of the size of the scratch, so it cannot be repaired and needs to be replaced.

The most difficult of these is determining the size of the scratch. It is a good idea to hit a 500-yen coin from the opposite side of the scratched part to check.

If these are not the case, you may be able to repair it yourself. Also, depending on the condition of scratches and cracks, it may be possible to repair even if the size is 500 yen coin or more.

Even small scratches may get worse after being left for a long time

Even if it is a small scratch that does not correspond to the above and does not block your view, do not leave it for a long time. The windshield while driving is exposed to strong wind pressure and also vibrates. Therefore, even if it is a small scratch, if it is left for a long time, the crack will spread and it may develop into a case that needs to be replaced.

Leaving scratches is absolutely NG!

If left for a long time, even if it can be repaired, the scratches may become clogged with dust and dirt, making it impossible to inject the repair agent. In that case, it is no longer possible to repair it by yourself.

Regardless of the situation, it is sure to have the contractor check the condition once.

Location and cost of windshield replacement and repair

Two choices, ask a vendor or fix it yourself

There are two options for windshield replacement and repair: ask a contractor or fix it yourself. You can repair or replace it by asking a glass shop or car dealer, but if you do it yourself, you can only repair minor scratches.

place repair exchange
Specialty store vendor From 15,000 yen 50,000-100,000 yen
dealer From 30,000 yen 50,000-100,000 yen
Work by yourself 2,000-4,000 yen ×

* In the case of exchange, it will be even more expensive, and it may be 50,000 to 100,000 yen.

If you work by yourself, the only cost is the purchase cost of repair kits. It’s cheap, but it comes with the risk of failure. On the other hand, if you ask a contractor, it costs money, but in addition to being reliable, you can also get accurate advice from an expert.

Is insurance covered for windshield repair costs?

© aengza001 /

If you apply insurance when you replace the entire windshield, the insurance grade will be reduced. As the grade goes down, the monthly premium payment will increase.

In some cases, it may be possible to reduce the burden in the long run by paying the repair fee yourself without using vehicle insurance. Talk to your insurance company about which is better.

Steps for first aid yourself

Get the tools you need

You can only work on your own to repair minor scratches. For repairs, use a tool such as a commercially available windshield repair kit. The contents are roughly as follows.

  • Repair liquid
  • Syringe
  • Pedestal * With adhesive tape

Recently, a type that dries the repair liquid with black light (UV light) is also on sale. Also, cheap kits may not include the following items, so get them as needed.

  • Dry rag or cloth (without damaging the glass)
  • Masking tape (for curing)

1. Clean the windshield

Gently wipe the area around the scratches on the glass with a dry cloth. Do not wipe with a wet object. If water gets in between the two pieces of glass, it will be difficult for the repair agent to get in.

2. Clean the inside of the scratch

Clean the inside of the scratch with a needle tip such as a thin pin to remove dust and dirt.

The purpose of this work is to remove excess material and at the same time make it easier for the repair liquid to penetrate. By lightly scratching the surface of the scratches on the glass, it becomes easier for the repair liquid to enter. Please do it carefully so as not to widen the wound.

Make sure to cure with masking tape

Protect the area around the scratch with tape to prevent the repair material from dripping. There is no problem if you skip this work.

3. Fix the pedestal to the scratch on the glass

It is a pedestal for injecting glass repair liquid into the wound and applying pressure. If this pedestal is not in close contact with the wound, it will fail without pressure. This work is important, so please do it carefully.

4. Inject the repair solution into the pedestal

The repair liquid does not penetrate the glass just by injecting it. The repair liquid has the property of hardening, so be careful not to pour it too much and wipe off any spills.

5. Repeat depressurization and pressurization

When the syringe is attached to the pedestal and the cylinder of the syringe is pressed to pressurize, the repair liquid is sent into the glass, and when it is pulled to reduce the pressure, the inner glass is pulled. By repeating this work about 10 times, the repair liquid and the inner glass are brought into close contact with each other.

6. Remove the pedestal

Remove the syringe and pedestal under no pressure. Wipe off any excess repair fluid that has spilled around and add a drop or two of the repair fluid to the scratched area of ​​the glass to fill the last dent.

7. Apply a protective film

Attach the protective film to the scratched part of the glass and wait for the repair liquid to solidify. It depends on the season, but it seems that it is about 30 minutes to 1 hour.

Check the manual that came with the repair kit.

8. Remove unnecessary repair liquid

Make sure that the repair liquid is completely solidified, and then remove the protective film. Even after the estimated time has passed, it may fluctuate depending on conditions such as climate. Curing is slower, especially in cold weather. Let’s check it carefully.

We will clean the part where the repair liquid has squeezed out from the scratch on the windshield. It is best to carefully scrape it off with a razor, but if you use the corner of the razor blade, the repaired scratch will recur. Remove only the excess repair liquid with the image of scraping off the part that protrudes from the height of the scratch.

It’s just a first aid

Repairs you do yourself are just a first aid measure to prevent the glass from deteriorating. Sooner or later you can be sure to ask a vendor for repairs.

Measures to prevent damage to the windshield

Drive to avoid stepping stones

Stepping stones are the most common cause of scratches on the windshield. Stepping stones are a phenomenon in which stones that are hit by the tires of the vehicle in front fly to the windshield while driving.

Since this is all luck, there is absolutely no way to avoid it, but if you pay attention to the following items, you can reduce the chance of suffering damage.

  • Keep a sufficient distance from the front
  • Keep legal speed
  • Avoid behind large vehicles such as trucks
  • Avoid behind sports cars
  • Avoid behind vehicles with wide tire grooves

Replace the deteriorated wiper immediately

Since the wiper is made of rubber, it will deteriorate if it is stored in a hot place. Continued use of the deteriorated and cracked wiper will damage the glass. The scratches can lead to cracks and eventually crack.

Do not pour boiling water over frozen glass

Moisture on the windshield of a car may freeze in cold weather or in cold climates. At that time, it is NG to pour boiling water to remove the ice. The temperature of the glass changes rapidly, causing cracks.

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