Seat belts

How do we know our seat belts are actually working? When strapped in and giving the belt a sharp jerk, it easily gives no tension,locks in place, or indicates that it will activate in an accident.

I think your best indicator would be a lack of incidents reported that the seat belts for your make,model,year failed to preform as designed.Do the belts retract normally? not frayed or dirty? not twisted? never been removed and re-installed.

I’m sorry, you might need to go back a rewrite that last sentence-- I have no idea what you’re saying.

It totally depends on what year make and model car you’re talking about. On most cars, you can give the seatbelt a tug and if they’re working, they’ll lock up, though there are some models that won’t do it in all circumstances.

Depends on how old the car is. Older seat belts used a friction lock that would lock the belt in place as a result of a sharp jerk, as you mention. Newer belts use inertia locks and move freely until the entire car accelerates in one direction or another.

To find out if your belts work, find an empty parking lot and accelerate to 25 mile per hour or so and hit the brakes sharply. As the car is rapidly slowing try pulling on the seat belt. It should have locked in place.

In the old days, retractable seat belts used an inertia roller system (I’m not sure of the exact name for it) that sensed how fast the belt was unspooling and locked it. I think the mechanism was something like the flywheel governor on an old steam engine. You could test it by yanking the belt hard to see if it locked up.

Newer cars use a mechanism that has a spring-loaded pendulum or something next to the belt spool, that swings forward or backwards enough in a crash to engage the spool and lock it. The upshot is that you can’t test it by yanking on the belt, only by braking very hard (maybe).

Try to lean forward when you step on the brakes or turn a corner. It wil probably hold then.

Find an empty piece of road, get up to about 30, and do a panic stop as if something had run out in the road in front of you. They should lock right up.