The natural cracking of the rear running lights of the car
The natural cracking of the rear running lights of a car (cracking without external force) is mainly caused by factors such as material aging, temperature stress, material or design defects, and improper installation.
Material and aging factors
Material natural aging: After long-term use, the material of the lamp cover gradually becomes brittle and loses strength due to environmental influences such as ultraviolet radiation and oxidation, resulting in cracks.
Material defects: Some through-type tail lights use materials that may have poor impact resistance and are not resistant to high temperatures, and are prone to cracking due to brittleness during normal use.
Temperature and environmental stress
Cold and hot alternating stress: The temperature of the rear lights changes frequently during vehicle operation, and the internal stress generated by the thermal expansion and contraction of the material may accumulate, potentially causing the lamp cover to crack naturally.
Environmental factors: Local overheating caused by moisture, water ingress, fogging, or circuit faults may also accelerate material deterioration and trigger cracks.
Design and manufacturing factors
Design or production defects: If the structure of the through-type tail light is unreasonable (such as insufficient heat dissipation or stress concentration) or the production process is not standardized, it is prone to cracking even without external force.
Installation errors: If the installation is unevenly stressed or has angle deviations, the lamp cover may have initial stress that leads to natural cracking over time.
When repairing the through-type lights of a car (usually referring to through-type tail lights or through-type LED light strips), special attention should be paid to the sealing, weather resistance, light transmission, and material compatibility. According to the latest publicly available information, the following types of adhesives are recommended:
Special repair glue recommendation
TADHE Vehicle Light Seamless Repair UV Adhesive
Main component: Modified acrylic UV resin
UV irradiation 5–15 seconds for rapid curing
High transparency, high hardness, resistant to 120°C high temperature, does not yellow under long-term exposure to sunlight
Can be directly polished and polished, with almost no trace after repair
Suitable for crack and defect repair of the lamp cover
Special sealing UV adhesive (such as TADHE Vehicle Light Sealing UV Adhesive)
Also of the modified acrylic UV resin system
Curing time 8–15 seconds, excellent waterproof and dustproof performance
Used to enhance sealing after repair to prevent moisture from entering the lamp body
Alternative solutions (suitable for non-professional operations or temporary repairs)
Epoxy resin adhesive
High bonding strength, corrosion-resistant, good temperature resistance
Requires mixing resin and curing agent in proportion, and the curing time is longer (usually several hours)
Suitable for deep or through-type cracks, but requires higher operation requirements
Silicone glass adhesive
Single-component, cures upon contact with air moisture
Strong weather resistance, adapts to temperature changes, good elasticity
Suitable for sealing joints or small cracks, but has lower transparency and hardness than UV adhesive
Adhesives not recommended
502 glue, ordinary AB glue, strong glue
Not resistant to high temperature and UV radiation, prone to aging and cracking
May corrode the plastic material of the lamp, causing the crack to expand
Poor sealing, unable to effectively prevent water and dust ingress
Precautions for operation
Clean the surface : Use a neutral cleaner + soft cloth to wipe the cracked area, and if necessary, use alcohol for degreasing.
Dry treatment : Ensure the repair area is completely dry to avoid water vapor residue.
Control the amount : Avoid spillage of the adhesive affecting light transmission or contaminating the interior of the lamp.
Curing conditions : UV adhesive requires UV lamp irradiation; epoxy adhesive requires sufficient curing time (usually 24 hours).
Safety assessment : If the crack length exceeds 5cm, has damaged internal circuits or reflectors, it is recommended to replace the assembly rather than repairing it yourself .
If unsure about the operation, it is recommended to handle it at a professional car repair shop to ensure driving safety.
If you want to know more, keep reading the other articles on this site!
Please call us if you need such products.
Zhuo Meng Shanghai Auto Co., Ltd. is committed to selling MG&MAXUS auto parts welcome to buy.
