Jacks lift, stands hold
A vehicle weighs thousands of pounds, and the safety of anyone near it depends on how that weight is supported. A jack is designed to raise a vehicle. It is not designed to be the thing that keeps it up while a person works nearby. Hydraulic jacks can leak down slowly or release suddenly, scissor jacks can tip or slip, and any jack can be knocked or shift if the vehicle moves even slightly.
Jack stands are built for the job of holding. They are mechanical supports with a locking mechanism, a wide base and a saddle that cradles a solid point on the vehicle. The standard principle is simple: lift with the jack, then transfer the weight to stands, and never put any part of your body under a vehicle supported only by a jack.
Stands come up in a lot of routine car maintenance, from tire rotations to oil changes, and they are among the automotive repair tools that matter most for safety rather than convenience. This article is general educational information. Follow your vehicle’s manual and the instructions that come with your equipment, and consider having a professional do any work you are unsure about.
How jack stands work
Most common stands use a ratchet-and-pawl design: a center post with teeth rises through a frame, and a pawl locks it at the chosen height. Others use a pin that passes through a hole in the post. Either way, the stand stays at its set height until the lock is released.
Stands are sold in pairs and are rated by a weight capacity, typically listed in tons. Often the stated capacity applies to the pair, not to each stand, so check the markings and the instructions. A rating should be treated as a maximum, not a target. Choosing stands with a comfortable margin over the weight of the vehicle is a reasonable approach. A light car, a pickup and a large SUV all differ a great deal, so look up your vehicle’s weight in the manual or door-jamb label.
What to look for
- A clear rating label and a wide, stable base.
- A secure locking mechanism that engages positively.
- Solid welds, no cracks, bends or rust damage.
- A saddle shape suited to the support points on your vehicle.
- Height range suited to the work you will do.
Inspect stands before each use. A stand that is bent, cracked, heavily rusted or has a worn lock should be retired. Avoid using stands in ways that exceed what the instructions allow, and avoid improvised supports. Cinder blocks, stacks of wood and bricks can crack or shift, so they are not substitutes.
The ground matters
A stand is only as stable as the surface beneath it. Level, solid ground such as a flat concrete slab is generally the preferred place. Soft ground, gravel, sloped driveways and asphalt on a hot day can all allow a stand or jack to sink or slide. If you cannot find a level, firm surface, the safest decision is often to postpone the job or have it done elsewhere.
Support points
Vehicles have specific locations designed to carry load for lifting and support, usually shown in the owner’s manual. These may be reinforced pinch welds, frame rails or other marked points. Using other places, such as floor pans, thin body panels or suspension parts that can move, risks damaging the car and leaving the stand unstable. The manual’s diagram is the best guide, and the same points are not always right for a jack and for a stand.
A general sequence
The exact method varies by vehicle and equipment, so use this as an outline only.
- Park on level, solid ground, set the parking brake and put the transmission in park or gear as the manual describes.
- Chock the wheels that remain on the ground so the vehicle cannot roll.
- Raise the vehicle with a jack at the lifting point from the manual.
- Place the stands at the specified support points and set them at matching heights.
- Lower the vehicle slowly until its weight rests on the stands, keeping the jack in place lightly as a backup rather than the main support.
- Give the vehicle a gentle shake or push to confirm it is stable before anyone goes underneath. Do this from a position where you are not under the vehicle.
Taking the weight off the stands again follows the reverse path: raise slightly with the jack, remove the stands, then lower slowly and clear tools and people from the area.
Habits that reduce risk
- Never get under a vehicle supported only by a jack.
- Avoid working under a vehicle on stands unless you are confident in the setup, and think about what you would do if something moved.
- Keep your body out of the vehicle’s potential fall path when applying heavy force. When loosening a tight fastener, use a breaker bar in a way that does not rock the car.
- Keep children and pets away from the work area.
- Do not run an engine in a closed garage, and be mindful of carbon monoxide.
- Wear safety glasses, since debris can fall.
Ramps and lifts
Drive-on ramps are another way to raise a vehicle, and they have their own cautions, such as making sure the wheels sit fully and the ramps are rated for the vehicle. Lifts are a different category entirely, and people who install a vehicle lift in a home garage need to follow the manufacturer’s installation and safety requirements closely.
When to stop
If anything feels unsteady, if the surface is questionable, or if a stand will not lock cleanly, lower the vehicle and rethink. A delay costs little compared with the consequences of a vehicle falling. Outcomes in an accident can be severe, and no equipment makes the work risk-free.