Working under a vehicle is one of the most dangerous tasks in basic car maintenance if you do not follow proper safety steps. A floor jack is designed only to lift the car, not to support its weight while you work underneath. Jack stands are the only devices that should hold the vehicle once it is raised. This guide covers how to use a floor jack and jack stands together correctly, from choosing the right equipment to lowering the car safely.
Jack versus Jack Stands
Many drivers assume that a floor jack can safely support a vehicle for an extended period. That is a misunderstanding that leads to serious injuries. A floor jack uses hydraulic pressure to lift the car, but that pressure can slowly bleed off, or the jack can fail suddenly if a seal blows. Jack stands are mechanical devices with a locking pin or ratchet bar that physically blocks the stand from collapsing. They are designed to hold a static load for as long as needed.
Never get under a vehicle that is supported only by a floor jack. Always use a pair of jack stands rated for the vehicle’s weight, and lower the car onto them before you slide underneath. The jack itself is a lifting tool, not a support tool. For more details on choosing the right equipment, see our guide on jacks, jack stands and ramps.
Choosing Ratings
Every floor jack and jack stand has a rated capacity printed on the label or stamped into the metal. This number is the maximum load the device can handle safely. You must select equipment with a capacity that exceeds the weight of the vehicle you plan to lift.
A common rule of thumb is to use jack stands rated for at least one and a half times the vehicle’s gross weight. For example, if your car weighs about 3,500 pounds, choose jack stands rated for 5,250 pounds or more per pair. The same principle applies to the floor jack: its rated capacity should be higher than the weight of the end of the car you are lifting, not necessarily the whole vehicle. Most passenger cars can be lifted safely with a jack rated for 2 to 3 tons, but always check the owner’s manual for the vehicle’s curb weight and the jack’s specifications.
Never exceed the rated capacity of any jack or stand. Using underrated equipment can cause sudden failure and collapse. If you work on heavier vehicles such as trucks or SUVs, choose higher-capacity stands and a floor jack accordingly. For a broader look at essential garage tools, visit our garage and car tools page.
Ground, Chocks and Parking Brake
Before you lift the car, you need to prepare the work area and secure the vehicle. These steps prevent the car from rolling or shifting while it is raised.
Choose a flat, solid surface
Place the floor jack and jack stands on a level, hard surface such as concrete or asphalt. Never work on gravel, dirt, grass, or loose pavement. An uneven or soft surface can cause the jack to tip or the stands to sink, leading to a collapse. If the only surface available is sloped or soft, do not lift the vehicle there.
Set the parking brake
Engage the parking brake firmly. For manual transmission vehicles, leave the transmission in gear (first or reverse). For automatic transmissions, put the vehicle in Park. This keeps the drivetrain locked and prevents the wheels from turning.
Use wheel chocks
Place wheel chocks behind and in front of the wheels that remain on the ground. If you are lifting the front of the car, chock both rear wheels. If lifting the rear, chock both front wheels. Press the chocks tightly against the tires. This is a critical safety step that prevents the car from rolling off the jack or stands if the parking brake fails.
Finding Lift Points
Every vehicle has designated lift points where the frame or reinforced pinch welds can safely support the weight. Using the wrong location can crush floor pans, damage brake lines, or cause the car to slip off the jack.
Open the vehicle owner’s manual and look for the section on jacking and lifting. It will show diagrams of the correct front and rear lift points. If you do not have the manual, look for reinforced metal flanges along the rocker panels under the doors. These are often the pinch welds that a scissor jack uses. For a floor jack, you typically lift from a more central point on the frame or a dedicated jack pad. Some vehicles have rubber or plastic jack pads that fit into the floor jack saddle.
Unless the owner’s manual specifically shows it as a lift point, never lift from the differential, the oil pan, the transmission pan, the suspension arms, or any plastic body panel. These parts are not designed to support the vehicle’s weight and can crack or bend. If you are unsure, consult a repair manual for your specific make and model.
Lifting and Placing Stands
Once you have the surface prepared, the parking brake set, and the wheel chocks in place, you can begin lifting.
Position the floor jack
Roll the floor jack under the vehicle and align the saddle with the correct lift point. Make sure the jack is centered and the saddle sits flat against the metal. Pump the handle slowly until the saddle just contacts the lift point, then double-check the alignment.
Lift the vehicle
Continue pumping until the vehicle rises high enough to slide the jack stands underneath. Lift a little higher than the height you need, because the stands will sit lower than the vehicle’s resting height. Leave enough clearance to remove the jack after the stands are in place.
Place the jack stands
Position the jack stands under the vehicle’s designated support points. These are often the same points used for the floor jack, or they may be slightly inboard on the frame. Adjust the stand height so it is as close to the vehicle as possible without touching. Most jack stands have a pin or ratchet mechanism that locks at set heights. Engage the locking mechanism fully.
Lower onto the stands
Slowly release the floor jack’s pressure valve to lower the vehicle onto the jack stands. Lower it gently until the full weight rests on the stands. Do not drop the vehicle. Once the weight is on the stands, give the vehicle a firm push at the bumper or fender to test stability. It should not rock, shift, or wobble. If it does, lift the vehicle again and reposition the stands.
The jack stands must carry the full load on their own. Some people leave the jack lightly raised under a separate solid point as an extra backup; if you do, never count on it to hold the car.
Before You Go Under
Before you slide under the vehicle, perform a final safety check:
- Verify that the parking brake is still engaged and the wheel chocks are still tight against the tires.
- Check that both jack stands are fully locked and sitting flat on the ground.
- Give the vehicle another firm shake to ensure it does not move.
- Make sure you have enough clearance to work safely. If you need more room, lift the vehicle higher and reposition the stands at a taller setting.
- Never work under a vehicle that is supported only by a jack, even for a quick task.
If you are performing a roadside tire change, use the scissor jack that came with the vehicle. Scissor jacks are designed only for temporary lifting to change a tire on a flat, level surface. They are not stable enough for any work underneath the car. For a complete list of emergency gear, see our roadside emergency kit checklist.
Lowering the Car
When you finish working under the vehicle, follow these steps to lower it safely:
- Remove any tools, parts, or equipment from under the car.
- Place the floor jack under the same lift point you used to raise the vehicle. Pump the handle until the saddle contacts the metal, then lift just enough to take the weight off the jack stands.
- Remove the jack stands one at a time. Pull them clear of the vehicle.
- Slowly release the floor jack’s pressure valve to lower the vehicle to the ground. Lower it in a controlled manner, not a sudden drop.
- Once the vehicle is on the ground, remove the wheel chocks and release the parking brake.
Never lower the vehicle by standing on the jack handle or by using any tool to force the release valve open. Use the jack’s handle as intended.
Inspection and Storage
Jack stands and floor jacks require regular inspection to remain safe. Before each use, check for these issues:
- Oil leaks from the floor jack’s hydraulic cylinder. A leaking jack may not hold pressure and should not be used.
- Cracks, bends, or rust on the frame or saddle of the jack or stands.
- A locking mechanism that does not engage fully or that slips under light pressure.
- Worn or missing rubber pads on the saddle or stand tops.
Store jack stands and the floor jack in a dry, clean area. Keep the jack’s hydraulic cylinder clean and lubricated according to the manufacturer’s instructions. If any component shows damage, replace it before the next use. Do not attempt to repair a damaged jack stand or floor jack yourself unless you have the proper parts and training.
FAQ
Can I use a floor jack alone to support the car while I work underneath?
No. A floor jack is only for lifting. It can fail or lose pressure without warning. Always use jack stands to support the vehicle before you go underneath.
How do I know if my jack stands are rated high enough?
Check the label or stamp on the stand for its rated capacity in pounds or tons. Choose stands rated for at least one and a half times the weight of your vehicle. For a 3,500-pound car, use stands rated for 5,250 pounds or more per pair.
Can I use a scissor jack from the trunk with jack stands?
Scissor jacks are designed only for roadside tire changes on level ground. They are not stable enough to lift a vehicle for work underneath, and they should not be used with jack stands. Use a floor jack for garage work.
Is it safe to place jack stands on asphalt?
Asphalt can soften in hot weather and cause the stands to sink. Concrete is the safest surface. If you must use asphalt, place a wide steel plate or thick plywood under each stand to distribute the load.
Using a floor jack and jack stands correctly is straightforward, but skipping any safety step can lead to a serious accident. Always lift from the manufacturer’s recommended points, use equipment rated above the vehicle’s weight, and never trust a jack alone to hold the car. With the right preparation and equipment, you can work under your vehicle safely and confidently.
