Why do you need a grade 8 bolt on struts, I have a 02 Ford Explorer xlt and I my friend just picked up a bolt and had me use it, it was 5/8?

Why do you need a grade 8 bolt on struts, I have a 02 Ford Explorer xlt and I my friend just picked up a bolt and had me use it, it was 5/8?

Added (1). 6 inches long with 2 inches of thread, should I be worried about them breaking a day after hitting pot holes…

Added (2). I'm guessing it was grade 4 or 5 since it was 5/8 diameter, but I have no way of knowing… I called them earlier and had them save the last 2 grade 8 bolts

Grade 2 bolts are not strong enough. Look for markings on the bolt heads.

The manufacture figures all of that out when he designs the car, so replace it with a like strength.