Jack Stands: Rating, Placement, and the Mistakes That Kill People

This is the one article on this site where getting it wrong has a body count. People are killed under vehicles every year, and the pattern is consistent: a hydraulic jack used as a support, on a sloped or soft surface, with nothing backing it up.

The rule

A jack lifts. A stand supports. Never get under a vehicle held only by a jack.

Hydraulic jacks fail by bleeding down — a seal weeps, a valve does not seat, and the load descends. It is not dramatic and it does not warn you.

Rating stands correctly

Stand ratings are given per pair, and the figure is the pair’s total capacity. A “3-ton” pair supports 3 tons combined, 1.5 tons per stand.

To size them:

Find your vehicle’s kerb weight (door jamb placard or manual).
You will be supporting roughly 60% of it when lifting one end, since weight distribution is not even and the other end stays on the ground.
Choose a pair rated comfortably above that, then add margin.

For a 4,000 lb (1.8 t) car, a 3-ton pair is appropriate. Do not run stands near their rating, and do not mix a stand from one pair with a stand from another — different heights and pin positions.

Surface first

Concrete, level, dry. That is the requirement.

Never on asphalt in warm weather. Stand feet sink into it, and a sinking stand redistributes load onto the other one.
Never on gravel, soil, or grass.
Never on a slope. Not even a shallow driveway camber.

If concrete is not available, stop. This is not a step to work around with a piece of plywood — plywood spreads load but does not make an unstable surface stable.

Placement

Use the manufacturer’s designated jacking and support points. They are in the manual, and on most unibody cars they are reinforced pinch welds or subframe points. On a body-on-frame vehicle, the frame rails.

What not to place under:

Floor pans, which will fold.
Suspension arms, unless the manual specifically says so.
The oil pan, gearbox, or any casting.
Plastic sill covers, which hide the actual pinch weld.

A pinch-weld adapter — a slotted rubber or urethane block — protects the weld and stops the stand slipping off it.

The procedure that makes it survivable

Level concrete. Engine off, in gear or park, parking brake on.
Chock the wheels staying on the ground, both sides.
Loosen wheel nuts before lifting, if you are removing wheels.
Lift at the designated jack point.
Place both stands at the designated support points, at the same pin height.
Lower the vehicle onto the stands slowly, watching that each seats squarely.
Leave the jack in place, just kissing the load. This is the redundancy that matters — if a stand fails, the jack catches it.
Shove the car firmly at the highest point you can reach before going under. If anything shifts, rocks, or creaks, start over.
Only then get under it.

Redundancy, stated plainly

Two stands plus the jack still in contact. If you have wheels off, put them flat under the sills as a third layer. None of this is excessive; the failure you are protecting against gives no warning and allows no reaction.

Things that are not jack stands

Concrete blocks. They crumble under point loads.
Bricks, timber stacks, wheels alone.
Ramps combined with stands at the same end.
A scissor jack from the boot, which is an emergency wheel-change tool only.

Inspecting them

Check before each use: welds intact, no cracks around the pin holes, ratchet teeth unworn, the pawl engaging fully, feet flat and not bent. Stands are cheap and steel is not forgiving of fatigue cracks. Replace anything you are unsure about — it is the least expensive decision in this entire article.

Ratchet stands vs pin stands

Two mechanisms, and they are not equal.

Ratchet (pawl) stands are the common type: a toothed column and a spring-loaded pawl. Fast to adjust, and the failure mode people fear — a pawl skipping under load — is real if the teeth are worn or the pawl is fouled with grit. Inspect the teeth before each use and keep the mechanism clean.

Pin-type stands use a solid steel pin through the column. There is no pawl to skip; the load bears on a pin in double shear. They are slower to set and generally the stronger design. If you are buying, these are the safer choice.

Whichever you have, both stands must be at the same height setting. A stand one notch different puts the vehicle on a twist and loads the two unequally.

Ramps, and where they fit

Ramps are safe for oil changes and anything needing only front-end lift with the wheels on:

Only on level concrete.
Chock the rear wheels, parking brake on, transmission in park or gear.
Drive up slowly and squarely; a wheel that climbs a ramp edge tips it.
Do not use ramps on a low front splitter — it will catch. Use longer, shallower ramps or drive-up blocks.

Ramps do not replace stands for wheel-off work, and never combine ramps at one end with stands at the same end.

Lifting on a slope, restated

There is no safe procedure for this. If the only surface available is sloped or soft, the options are a mobile mechanic, a workshop, or waiting. A car on stands on a driveway camber is a car that will move eventually, and it moves in the direction of the person under it.

Working under a car properly

Wheels off? Put them under the sills flat, as a third layer of protection.
Keep your body out of the crush zone wherever possible: work from the side rather than lying fully under the centre.
Have a phone in your pocket, not on the bench.
Tell someone you are under a car, especially if you are alone in a garage.
No hydraulic-only support, ever, including a two-post lift that has not been locked onto its mechanical latches.

Inspecting and retiring stands

Before each use, check:

Welds at the base and around the column — hairline cracks are the failure precursor.
Pin holes for elongation, or ratchet teeth for rounding.
The pawl engaging fully and positively, with its spring intact.
Feet flat, unbent, and not corroded thin.
No bending in the column.

Retire anything with a crack, a bent leg, or a pawl that does not seat crisply. Stands are among the cheapest tools in the garage and the only one whose failure is likely to be fatal. There is no economic argument for keeping a doubtful one.

What good practice looks like in one paragraph

Level concrete, engine off, parking brake on, wheels chocked, lift at the designated point, two matched stands at the designated support points set to the same height, vehicle lowered onto them slowly, jack left in contact as backup, wheels stowed underneath, and a firm shove test before any part of you goes under. That sequence takes three extra minutes and it is the difference between a job and an incident.