How Do Seat Belts Work and What Happens if They Break

Seat belts have been an essential safety feature in cars for over half a century and have been shown to significantly reduce the risk of death and serious injury in the event of a collision. But how do seat belts work, and what should you do if they break? 

No one wants to be involved in a collision, but accidents happen. Maintaining the safety and functionality of your seat belts will help protect yourself and any passengers in the event of a crash or sudden stop. Keep reading to learn about seat belts and how to prevent failures before they happen.



How do seatbelts work

How do seat belts work during a crash?

Seat belts are made of tightly woven fabric and are strapped across the lap and over the shoulder to keep the wearer in place during a crash. When a car breaks suddenly or collides with another object, the change in momentum can cause drivers and passengers to be thrown from their seat. 

Wearing a seat belt is the best way to ensure that you are protected in these situations. Seat belts work via an internal retraction system, in which a spool and spring box allow the fabric to be adjusted by the wearer. The spool is fitted with a highly effective locking system that is triggered by sudden movement of the vehicle and secures the wearer during a crash.


Can seat belts break?

There’s no doubt that wearing your seat belt is essential to road safety and they save thousands of lives each and every year. But like with any physical mechanism, it is possible for them to break or fail. That’s why it’s a good idea to periodically check that your seat belts are in working condition, particularly in older cars. Car seat belts have progressed significantly since their introduction, and it’s important to remember that seat belt mechanisms in older vehicles can be less advanced and more susceptible to wear and tear.

Even in newer cars, it’s generally recommended to have your seat belts examined regularly, especially after a collision, and it’s a good idea to have them replaced every 10-15 years.


Causes for Seat Belt Failure

Understanding how seat belts work and the components that help them function properly can be extremely helpful when it comes to ensuring safety in the case of a collision. That’s why we’ve created a guide to teach you about the potential causes of seat belt failures and how to prevent them so you can feel safe and secure on the roads.



How seat belts work


The buckle is what allows you to secure the fabric of the seat belt to the seat of your car via a metal tongue. When the internal structure of the buckle is damaged or blocked, this can prevent the belt from properly latching, which can cause it to disconnect during a collision. When you insert the tongue into the buckle, always listen for a click that indicates proper latching. It’s also a good idea to tug on your belt after you’ve latched to ensure that it won’t break. If you’re unable to latch your seat belt, take your car to a trusted auto body repair shop like Mackin’s to have it checked out.



Pretensioners are what cause the belt to actively retract and pull the wearer into the safest position during a crash. Most pretensioner systems are gas-fueled pyrotechnic devices, which means that, once the sensors are ignited, the component must be replaced to function properly. That’s why you should always have your seat belt replaced after an accident to prevent the pretensioner from failing in the future.



what are seatbelts made of

Seat Belt Webbing

We all know we rely on them to keep us safe, but what are seat belts made of? Modern seat belt webbing is usually composed of 100% polyester, which is exceptionally sturdy and able to stand up to most physical force. However, nylon was the standard fabric in seat belt construction for many years, and it’s more susceptible to wear and tear, especially in the event of prolonged friction with sharp objects. 

If you have an older car, it’s recommended that you have your seat belts examined and replaced if they’ve sustained damage from aging. Broken webbing in newer models is usually due to a manufacturing defect, which is why it’s a good idea to have brand new cars checked to ensure they are properly constructed.


Seat Belt Anchors

Seat belt anchors are what secure the system to the interior of your vehicle. Of course, if the anchor is faulty or not installed properly, the seat belt can become detached and no longer provide the security you need. Typically, seat belt anchorage failures are due to manufacturing errors, which is why you should always have your new car inspected for potential issues before hitting the roads.


Getting Your Seat Belt Repaired

A working seat belt is one of the most effective defenses in the event of a crash, and can protect you and your loved ones from serious injury or death.

To maintain your seat belt between inspections, always keep the area around the buckle clear and test the latch regularly. Dirt around the buckle or the belt itself can also lead to wear and tear, so it’s a good idea to check the webbing for damage and clean it with mild soap and water if soiled.

If you suspect that any part of your seat belt system may be damaged, it’s important to have it inspected as soon as possible. It’s also important to remember that seat belts often break during a crash and should be looked at and repaired or replaced immediately after a collision.


The Seat Belt Repair Process

Repairing a seat belt is usually fairly straightforward, but the repair process will depend on the make and model of your car, the cause of the damage, and the components that need to be repaired or replaced. 

Current global supply chain issues have unfortunately extended auto repair times due to a shortage of essential parts and longer shipping times. However, at Makin’s, we know how to fix a seatbelt quickly and effectively and we’re dedicated to keeping you updated throughout the process and getting your vehicle in top condition as soon as possible.



old time photo

Learn How Mackins Can Help!

Mackins Auto Body has been offering effective and reliable collision repair in the Portland and SW Washington area for over 75 years. When you bring your car in, you’re guaranteed to receive the high-quality repair services you need to get back on the roads safely and as soon as possible. We offer experience and expertise in collision repair no matter the extent of the damage. 

Contact us or visit one of our 10 locations to get started! You can also check out our frequently asked questions for more information about our services.

Chris Roberts

Chris Roberts

Chris Roberts is the Director of Operations at Mackin’s Auto Body, where he has been making an impact since 2018. With a career in collision repair that started in 1999, Chris brings a wealth of experience and dedication to his role. Before stepping into his current position, he served as the Assistant Operations Manager at Mackin’s Auto Body from 2013 to 2017. Chris holds a BA from Northwest Nazarene University. When he’s not ensuring everything runs smoothly at Mackin’s, you can find him skiing down snowy slopes, wake surfing on sunny days, or cheering on his daughter at her soccer games.