What a jack does and why you need the right one for suspension work

A jack is a mechanical device that lifts your vehicle off the ground so you can access the suspension components underneath. For suspension work — whether you're replacing struts, inspecting bushings, or changing springs — you need a jack that can hold the vehicle stable while you work, not just lift it briefly to change a tire.

The difference matters. A scissor jack (the small diamond-shaped one that comes with most cars) can lift a corner of your vehicle, but it's not designed to hold it safely for extended work. Suspension work requires either a floor jack paired with jack stands, or a lift system that can support the full weight of your vehicle for the time it takes to complete repairs.

Before you start any suspension work, you also need to understand where on your vehicle's frame it's safe to place a jack. Using the wrong lift point can damage your car's undercarriage or cause it to slip during work — a serious safety hazard.

Key Takeaways

  • A floor jack lifts your vehicle, but jack stands must support it while you work — never work under a car supported only by a jack.
  • Your vehicle's manual or the placard inside the driver's door shows the correct lift points for your specific make and model.
  • Suspension work requires lifting the entire side or both sides of the vehicle, not just one corner, so plan your jacking sequence before you start.
  • Always place jack stands on a level, solid surface like concrete, and keep the jack in place as a backup even after stands are positioned.

Floor jacks versus scissor jacks and lift systems

A floor jack is a wheeled hydraulic device that sits under your vehicle and lifts it by pumping a handle. Floor jacks come in different weight ratings — typically 2 to 5 tons — and you need one rated for at least your vehicle's curb weight (the weight when empty). A 3-ton floor jack works for most sedans and small SUVs; larger trucks and SUVs need 4 or 5 tons.

The scissor jack that comes with your car is portable and fine for roadside tire changes, but it's not stable enough for suspension work. It can slip, and it doesn't leave you enough clearance to work comfortably underneath.

If you have access to a two-post or four-post lift at a garage, that's the safest option for suspension work because the lift is designed to hold the vehicle securely for hours. At home, a floor jack plus jack stands is the standard approach. Jack stands are metal stands with a flat top that sit under the frame and hold the vehicle's weight while you work. You always use them in pairs (at minimum), and you keep the floor jack in place as a backup.

Finding the correct lift points on your vehicle

Every vehicle has specific points where it's safe to place a jack or jack stand. These are reinforced areas of the frame designed to handle the vehicle's weight. Using any other point — like the plastic trim, the door sill, or a random spot on the undercarriage — can puncture fuel lines, damage brake lines, or cause the vehicle to slip.

Your vehicle's owner's manual shows the lift points in a diagram, usually in the section about changing a tire. If you don't have the manual, check the inside of the driver's door jamb — many vehicles have a placard showing lift points there. You can also search online for "[your year, make, model] lift points" to find diagrams.

For suspension work on the front end, the lift points are usually reinforced areas just behind the front wheels, on the frame rails. For the rear, they're typically on the frame rails just in front of the rear wheels. When you're lifting one side of the vehicle, place the jack under the correct point on that side, and place jack stands under the same frame rail on both sides of that end.

The step-by-step process for jacking up your vehicle safely

Step 1: Park on level ground. Choose a flat, solid surface like concrete or asphalt. Avoid gravel, dirt, or sloped driveways — the jack can sink or slip. Turn off the engine, engage the parking brake, and chock the wheels that will stay on the ground (use wooden blocks or wheel chocks behind and in front of the wheels).

Step 2: Locate and mark the lift points. Using your manual or the placard, identify where the jack goes. If you're lifting the front end, you'll place the jack under the front lift point on the side you're working on. Mark these spots with chalk or tape so you don't lose them once you're under the car.

Step 3: Position the floor jack. Roll the floor jack into place so the lifting pad sits directly under the lift point. The pad should be flat against the frame, not tilted. Pump the handle slowly to raise the vehicle a few inches — just enough to see that the jack is stable and the pad hasn't slipped.

Step 4: Position the jack stands. Once the vehicle is lifted a few inches, slide the jack stands into place under the same frame rail, on both sides of the vehicle if you're lifting one end. The stands should be at roughly the same height as the floor jack's pad. Lower the vehicle slowly onto the stands by releasing the floor jack's pressure valve (usually a small lever or screw). The vehicle should settle onto the stands, not rest on the jack.

Step 5: Verify stability before working. Once the vehicle is on the stands, gently push on the vehicle to make sure it doesn't rock or shift. The stands should be firmly planted and the vehicle should feel solid. Leave the floor jack in place as a backup — don't remove it.

Common mistakes that create safety hazards

The most dangerous mistake is working under a vehicle supported only by a floor jack. Jacks can fail, leak hydraulic fluid, or slip off the lift point. Jack stands exist specifically to prevent a vehicle from falling on you if the jack fails. Always use stands, and always keep the jack in place as backup.

Another common error is lifting from the wrong point. Lifting from the plastic trim, the door sill, or a random spot on the undercarriage can puncture fuel or brake lines, or cause the vehicle to slip. If you're not certain where the lift point is, don't guess — look it up in the manual first.

Lifting on an uneven surface is also risky. Gravel, dirt, or a sloped driveway can cause the jack to sink or the stands to tip. If you don't have a level concrete surface, you can use plywood sheets to create a stable base, but concrete is always better.

What to do if you need to lift both sides of the vehicle

Some suspension work requires lifting both the front and rear of the vehicle at the same time — for example, if you're replacing all four springs or doing a full suspension inspection. In this case, you'll need four jack stands (two pairs) and a plan for the lifting sequence.

Lift one end first (usually the front), place stands under both sides of that end, then lower the floor jack. Move the floor jack to the other end, lift it, and place stands under both sides. Once all four stands are in place and the vehicle is settled, you can remove the floor jack entirely and work on both ends.

If you're using a two-post or four-post lift, the lift itself handles this — it raises the entire vehicle at once and holds it securely.

Frequently Asked Questions

Can I use ramps instead of a floor jack and jack stands?

Ramps can work for some suspension inspections where you only need to see underneath, but they don't give you the clearance or stability you need for most suspension repairs. Ramps are also harder to position precisely under the lift points. A floor jack and jack stands are the standard for suspension work at home.

What size floor jack do I need for my vehicle?

Check your vehicle's curb weight in the owner's manual, then buy a floor jack rated for at least that weight. Most sedans need a 2 to 3-ton jack; SUVs and trucks typically need 4 to 5 tons. It's better to have a jack rated slightly higher than you need than one that's barely adequate.

How high do I need to lift the vehicle for suspension work?

Lift it just high enough to place jack stands underneath and give yourself room to work. Usually that's 12 to 18 inches off the ground, depending on the suspension component. You don't need to lift it as high as possible — higher lifts are less stable.

Can I work on suspension if I only have a scissor jack?

No. A scissor jack is not stable enough for suspension work and doesn't leave enough clearance. Borrow or rent a floor jack and jack stands, or take the vehicle to a shop. The cost of renting is far less than the risk of a vehicle falling on you.

Do I need to turn off the engine before jacking up the vehicle?

Yes. Turn off the engine, engage the parking brake, and chock the wheels before you start jacking. This prevents the vehicle from rolling or shifting while you're working underneath it.