If the car is firmly situated on the jack stands then , yes, it's safe. Just make sure that the entire top of the jack stand surface is in contact with the cars frame or suspension member, not just sitting on a corner or edge. At least two stands should be used and four are better. I always kick the bumper and rock the car a few times before getting under it when I have to use jack stands just to make absolutely sure it isn't going to slip.
Not always! There's always a chance that the car will fall on you. All you can do is try to make that a very slim chance. I was living in an apt complex, I noticed a friends jack stands were sinking in the asphalt, so I took my jack stands to work and welded 2x2 'feet' on the bottom of each leg, now I can use them even in sand, they won't sink! To ensure the jack stands don't sink I also set them on a 12in long piece of 2x10 (pressure treated) Before you crawl under a car, give it a GOOD shake, if it's solid then your good. Use your jack stands, if your car falls can you lift it off yourself? Don't use concrete cinder blocks, I've seen that, they tend to crack and drop the car.
No, its not always safe. Depends on the quality of the jack stands as well as the positioning under the car. Use the pinch rails or subframe.
no. The car can still tip over. I usually have the jack set as the backup.
One jackstand: unsafe. They sell them in pairs for a reason. Play it extra safe and use 4.
It is not save unless you have multiple jackstands as backup.
I don't own a hoist, but I do have jack stands and jack to work under the car. I would like to know, is it always safe? Could it fall down anytime on top of me?
