While the scissor jack in your trunk is fine for emergency wheel changes, when it comes time to working underneath your vehicle, a floor jack and two or more sturdy jack stands are the proper tools for the job. A heavy-duty floor jack used in conjunction with jack stands will provide safe vehicle support. Never work under a vehicle supported by a car jack alone.
Car jack types
Floor jack and jack stand sets are more affordable than ever. Everything from smaller, lightweight one-ton to super duty five-ton models can be found for a reasonable price. Determining which setup you need depends largely on the weight of your vehicle. There's no need to get a five-ton set if you drive a compact import, and a one-ton set won't cut it for lifting a full-size SUV.
Another important factor to consider is vehicle ground clearance. Low-profile floor jacks are designed to squeeze into tight spaces. Some sportier cars and trucks have ground-hugging front-, rear- and side-mounted aerodynamic body panels that require a low-profile floor jack for clearance. If you can't get the jack under the vehicle, you're back to square one.
Jacking up a car
The procedure is to raise a vehicle high enough to get the jack stands underneath, and then slowly lower the vehicle onto the stands. Once the vehicle is secure on the stands, the car jack can be removed, allowing you to work safely underneath. The very first step is to park the vehicle on solid, level ground such as a concrete or paved surface. Place the vehicle in park, set the emergency brake or use a wheel chock to prevent the vehicle from moving.
Where to put a jack on a car
Jacking and jack stand support points are also extremely crucial. A car jack or jack stand in the wrong location can cause vehicle or bodily damage. Your owner's manual is a good place to find safe jacking locations for your vehicle. Never jack up a vehicle from a point not designed to handle the load. If unsure about where to place a jack or jack stand, the best strategy is to stop. Do not attempt to guess at a good location. You can easily put holes in your floorboards.
Lowering a car
When lowering a vehicle onto jack stands or back onto the ground, it is important to gently release the hydraulic pressure inside the car jack. Before lowering the vehicle, always double-check your jack stands, or make sure the area is clear by looking and loudly saying "clear!" Slowly lowering a vehicle not only prevents damage, but gives you time to see any potential hazards before they occur. Practice raising and lowering the car jack to get a good feel for how it operates before attempting the real deal.
After the vehicle is up and on the jack stands, always check for solid support before attempting to work underneath. The best way to do this is to grab onto the bumper and give the vehicle a quick back and forth shake. It's much better to determine if the vehicle is solidly supported while you're above it then when underneath. The wheel chock is a good idea for an extra margin of safety once you have performed this test. Take it slow the first time around and soon you will be raising and lowering your vehicle like a pro.