How to raise a vehicle safely by using a jack
Jacking may seem simple, but doing so without damaging your car isn't always straightforward. Like anything else in life, a little planning goes a long way.
The most common damage usually occurs with the use of what's known as a floor jack, which is a lot more substantial and easier to use than the lightweight toys automakers think should suffice as an emergency jack. Someone will invariably put the jack's contact pad against something underneath the body that won't support its weight without bending or breaking. The first general rule of thumb is to check a vehicle's owner's manual to see if it identifies proper jacking points.
The problem with using the supplied jack's instructions for a tire swap is that most of these cheesy scissor jacks have heads designed to engage the ridge where the floor pan and rocker panels meet, often referred to as a pinch weld. These areas are strong and useful enough when a vehicle is young and rust-free, but they're also the area first attacked and weakened by corrosion.
If it looks like it moves, don't put a jack under it. People have damaged driveshafts, CV axles, steering tie rods, stabilizer bars and more when they ignore this rule.
Most vehicle floor pans have reinforced ridges or frame rails that can provide safe lift points for a rolling floor jack. If you're a stickler in not damaging any finishes, even on the under carriage, get a good quality jack with a rubber contact pad and a sufficient weight rating.
Taking shortcuts by trying to lift the entire front or back of the vehicle with only one jack placement is risky. Yes, there usually are solid lifting spots found at the bottom of the front and rear suspension cradles, but vehicles aren't balanced down their centre line. Fuel tank placement, along with other equipment and components, can make one side heavier than the other, and trying to balance all this on a floor-jack head only a few inches wide can lead to disaster if the vehicle slips.
There's a reason good jacks have wheels on them, and it's not just to make them easy to move around. When lifting a vehicle, the higher it goes, the more off balance the jack can become, unless it or the vehicle can move. Most safety-minded techs will block the wheels or use the parking brake to keep the vehicle from moving, so the jack has to shift slightly on its wheels. It's another good reason to always keep an eye on things when raising or lowering a vehicle with a jack.