Hot answers tagged

99

The ONLY time you should crawl under a car is when it is supported by a jack stand or on a lift. A jack is used to jack the car up and let it down. It is a huge safety concern to use it to support the car while crawling under it. You can kick the tire from the outside of the car if it won't come off, but keep your body parts away from underneath the car. ...


51

There is no such thing as "absolutely, perfectly, 100% safe." Each tool has its proper and improper uses, and each works either in parallel with other tools to increase safety and dependability, or in series with other tools ultimately reducing safety and reliability. Will a hydraulic jack hold up a car safely? That depends on the level of risk you're ...


39

Yes, you do have something to worry about. Even with a lot of weight on a jack, the jack could move, either back and forth, or side to side, and the whole shebang could pivot down until the car rests on the ground. Hydraulic jacks are indeed easier to use, but even they can fail. Would you like to be lying underneath when one of the hydraulic seals lets go ...


33

You can use either jack you want For safety sake, don't get under the car unless you have some jackstands. It isn't the jack failing that kills you. It's the fact that you only used a jack and didn't have any backup. You NEVER use a jack alone if you are getting underneath the car. You ONLY use a jack to change a tire on the side of the road and you ...


26

What you did was dangerous, there are Darwin Awards for just this type of thing! The likelihood of something going wrong is low, but the consequences are terrible if it does. There are many failure modes when jacking up a car: Scissor jacks are pretty reliable but they can fail, the ground could be unstable or the surface could collapse due to the weight. I'...


25

TL DR: Nope, I'd say not. When I was a young man, my Dad always told me, "Use the tool which is designed for the job." For instance, if you are trying to remove a bolt out of your suspension holding an A-Arm, you wouldn't use a body hammer to move it out, you'd use something with a little more heft, like a 5lb sledge or something similar. I'm sure if you ...


17

Assuming you had to do this on the road (why else would you want to put a donut on?), I wouldn't go under the car no matter how steady it is, even on a jack stand on a completely flat patch of concrete. In case someone crashes into your car, you're toast. In case of a car jack, it could be enough for a big vehicle to drive close to your car and blow it out ...


16

No, I thought it could as well. One time I had a Corolla up in the air while I battled with a speedometer cable (which meant I was going in from the top of the car, underneath, and through the wheel arch). I walked away from the car to get a spanner, I came back and I was looking at where to remove a bolt. I then noticed the car was very low down. The jack ...


15

Even if you had supported the car properly with jack stands, it was still a huge mistake to kick it or exert force on it. Even jack stands are not so stable that they can handle a lot of dynamic side-load. This was a very foolish thing to do. What made this even worse is you were under the car. There's an old saying about the risks of being killed by a ...


13

Leaving the car jacked for a long time is very risky: remember jacks are designed with systems for lifting and lowering a load. Some use hydraulics, other a screw type system but all of them works under a lot of stress because the huge load they need to handle. They should be solely used only for lifting, then use a jack stand to do the load support job. ...


13

NO, and I don’t understand why you don’t refer to standard workshop practise which is to lift the vehicle and then put proper stands under it. Sadly there are too many accidents of either vehicles or tipper trailers falling due to the failure of hydraulics and injuring or killing people. Don’t rely on hydraulics to keep the mass in the air: stands or ...


12

Yes, wheel chocks would help in this case. Also, use of the emergency brakes as well as leaving it in gear (EDIT- Leave it in gear if a manual or park if automatic). If wheel chocks are not available, you could use a largish stone which could be wedged between the tire and the ground on both sides of the tire. This would be on a tire which is not flat and ...


12

I have seen a lot of qualified mechanics leave the car on jack stands for months without any problems. It is more a question of where the car is being stored while on jack stands. In a garage where it is safe from accidentally being leaned on and possibly tipped over would be best (and out of sight from vandals/hooligans that might want to cause havoc, ...


11

Stands are simple mechanical devices in the sense that typical failures (cracks, bends) are easily observable by a simple visual inspection. That's what makes them inherently safe. A hydraulic jack on the other hand is sophisticated enough to have hidden failure modes (leaky seals / valves, etc.) which are not instantly obvious and can be easily overlooked. ...


9

If where you are putting the vehicle up at is level ground (driveway, for instance), there is plenty of support under the jack stands (like concrete pad), and you are putting the jack stands at secure locations under your vehicle extended the same amount (so vehicle is level), you will have no issues what-so-ever. Vehicles which are suspended like this are ...


9

I'm not sure what it specifically says, but it is indeed not safe to be under a car that is supported only by a jack, hydraulic or mechanical. To be safe, get a pair of jack stands, and use whatever jack you want to raise the car high enough to put the stands in place, then lower it so vehicle is resting on the stands. The jack that comes with the car ...


9

There's a difference between a jack and a jack stand. I've left vehicles on jack stands for days, even weeks, but a jack, regardless of type, is prone to failure: they are designed to raise and lower, not to hold. A jack stand on the other hand is a solid piece of metal and is designed to hold. If you don't have jack stands, I strongly recommend you ...


9

No it's not the same as a jack stand or even a brick or a tire on its side. My primary fear/experience is that a jack will tip. Adam Davis explains the risk of slow leakage, which is a thing, but your more direct risk is of the jack toppling over. Look at the design of a jack stand: it's wide at the bottom and has no wheels. Now look at a jack. Other than 4+...


8

Hydraulic jack seals blow. Because hydraulic jack seals blow one should never put body parts under a load (vehicle) raised with a hydraulic jack. Let me state that again so that it sinks in: Hydraulic jack seals blow. Using jack stands is like wearing seat belts. It might take years until you get into a car accident or see a jack seal blow. But after it ...


8

Never, EVER get under a car supported by a hydraulic jack alone. You MUST use jack stands (or something equivalent) or you are practically begging for a Darwin Award. Consider that if you use a hydraulic jack alone to support a car and then crawl under it, your life is now down to the quality of a 10 cent o-ring that was probably bought on the "low bid" by ...


7

The differences between the floor jack and the tranny jack: Tranny Jack has 4 points on a metal plate that can be adjusted to change the angle of the tranny jack and how it meets up with the transmission. This feature is necessary. Tranny jack has a very wide stance to prevent a top heavy jack from falling over with an incredibly heavy item. A wider base ...


6

We have a few project cars and have left them on jack stands for long stretches of time while we were rebuilding stuff. I'll second Tariq that if the vehicle is held up at proper jack points you should have no problems. It's also a good point to have the vehicle somewhere secure, if only to keep curious people, pets, etc from crawling underneath and ...


6

You have a great answer but more to add than just a comment Have jack stands and a plan Position the car on a flat surface solid surface and give yourself work room Lay out the tools and parts Emergency brake, park or reverse, and chock(s) Have a plan for exactly where you are going to jack and place the stands The owner's manual should have in ...


6

If you leave the car in gear, and depending on if the vehicle is front-wheel, rear-wheel drive, don't jack both front wheels up if front-wheel drive, etc. This way you always have a tire on the ground that is in gear. So if your left-front tire blew out and your car is front wheel drive, jack it up so the right-front wheel stays fully weighted on the ground. ...


6

It's not safe. The probability for a jack to lose pressure slowly and even rapidly due to extreme failure is exponentially higher than a welded jackstand coming apart. Also there's the argument that jacks do not have a equal footprint meaning they are more susceptible to tipping over one way over another. Jackstands don't have this issue, as the base is ...


6

Don't hammer a rim... even a steel one can deform and then it is a bin job but an alloy is pretty easy to damage. Frankly with a wheel stuck on there are a couple of less dodgy options (and if it is for changing a flat then pump it up first - they are rarely so flat they won't hold air for a bit) Put the wheel nuts in loose (enough to stop wheel falling ...


5

I'm assuming you are saying you are going to purchase a used "hydraulic" jack? If so, the main thing to look out for is if it is leaking or not. If it's a scissor style jack, ensure smooth operation. Test out the jack to ensure it works, such as does it smoothly jack your car up? Does it smoothly let your car down? Make sure YOU know how to use it. A used ...


5

In the first picture where you have the orange circled item ... just to the left of it (in the picture) there is a large bolt which attaches the circled item to the body. This would probably be a good lift point. I've found that anywhere which is going to be used as a bolted mount point is going to be very sturdy. If you are worried about marring the bolt, ...


5

Jackstand points on that car should be placed on the pinch welds near the door. underneath the car toward the front. Where to properly jack up and support a car In that video he explains how to do it. NEVER under any circumstances should you place jackstands underneath suspension components, or anything that has the capacity to move around in any axial ...


5

I've pulled a car clean off a jack before. Just don't. In many case the handbrake was stuck on (broken spring) and the ground wasn't great so as soon as the load on the jack was slightly off vertical it dug in and kept going down.


Only top voted, non community-wiki answers of a minimum length are eligible