Car Jack Failure During Tyre Change Assistance MyMechanic

Stabilise first, not later

• Hands clear: if the vehicle has dropped, do not reach under the sill or wheel arch; move everyone to the safe side.
• Hazards and triangle: make the scene visible, keep traffic‑side doors closed.
• Parking brake and gear: auto in Park; manual in first or reverse; on slopes, point front wheels toward the verge.

• Chock the wheels: proper chocks if available; otherwise rocks, bricks, or a thick block of wood—both sides of the tyre opposite the lifted corner.
• Use the spare as a safety block: slide it (on its side) under a strong underbody point near the dropped corner.
• Create a firm base: place a solid board under the jack to spread load and prevent sinking on soft or uneven ground.

Inspect before a second lift

• Jack condition: if bent, leaking, or saddle pin damaged—stop DIY and request assistance.
• Jacking point: use the marked pinch‑weld or reinforced point; avoid body panels or thin seams.
• Wheel nuts: if partially installed, finger‑tighten in a star pattern before any lift.

• Level, solid ground only—no soft soil or steep camber.
• Lift just enough to clear; keep the spare or timber under the sill as secondary support.
• Star pattern: lower until the tyre kisses ground, tighten in a star pattern; after full lowering, re‑torque and recheck after a short drive.

• Any body contact with the ground or undertray damage.
• Bent jack, distorted pinch‑weld, or collapsing ground under the jack.
• Night, heavy rain, fast traffic, or narrow shoulder.
• Locking wheel nut key missing or nut edges rounded off.

Preventing the next jack failure

• Base board in the boot: 25–30 cm square of hardwood/plastic.
• Proper chocks: lightweight polymer chocks stop roll‑back.
• Weekly glance: jack, wrench, spare pressure, and locking key present and reachable.

If the car fell with the wheel off

• Don’t rush: slide the spare under a sturdy point first as a fail‑safe; reposition the jack carefully on the marked point.
• Check brake line/sensor wiring: if stretched or damaged, stop and request towing.
• Hub and studs: ensure studs are straight and threads clean; start nuts by hand to avoid cross‑threading.

If the jack is stuck under the sill

• Do not yank sideways: lift the car a few millimetres with a second jack or lever a thick board under the opposite side to relieve pressure, then remove gently.
• If unavailable, wait for assistance: forcing a trapped jack can tear the sill seam or slip dangerously.

• Gear that fits: stable jacks, wide base plates, chocks, low‑profile equipment, and proper lighting for night or rain.
• Damage‑aware handling: quick checks of studs, brake hoses, sensor wires, and undertrays before refitting or towing.
• Clear finish: star‑pattern torque, spare pressure, and retorque guidance after a short drive.

Frequently Asked Questions