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Question

Difficulty: EasyWheels and Tires

An automotive technician needs to replace a flat tire with a spare wheel. In what chronological order should the technician perform these steps to ensure safety and proper wheel mounting?

  1. 1Break the lug nuts loose by loosening them slightly while the tire is still in firm contact with the ground.
  2. 2Raise the vehicle using a service jack and support the frame securely on a jack stand.
  3. 3Remove the loosened lug nuts, take off the flat wheel, and mount the spare wheel onto the hub studs.
  4. 4Lower the vehicle completely to the ground and torque the lug nuts in a crisscross pattern to manufacturer specifications.

Answer

1. Break the lug nuts loose while the tire is on the ground; 2. Raise the vehicle and secure it on a jack stand; 3. Remove lug nuts, take off the flat wheel, and mount the spare wheel; 4. Lower the vehicle to the ground and torque the lug nuts in a crisscross pattern.
The correct sequence begins by breaking lug nuts loose while tire traction keeps the wheel stationary, followed by lifting and securing the chassis on a stand, changing the wheel assembly, and finally lowering the vehicle before applying specified final torque in a crisscross pattern.

Step-by-Step Solution

1
Loosen each lug nut approximately one-half turn before elevating the vehicle.
The initial high-torque resistance is overcome safely without spinning the wheel or risking vehicle instability.
Ground contact prevents wheel rotation and provides stability under heavy breaker-bar torque.
2
Elevate the axle or lift point using a mechanical or hydraulic jack, then place a rated jack stand under the designated chassis point.
The tire clears the floor and the vehicle is mechanically supported.
Jacks are lifting devices, not long-term holding devices; jack stands prevent accidental drops.
3
Spin off the remaining lug nut threads, slide the flat tire off the hub studs, and mount the spare wheel flush against the hub face.
The flat tire is removed and the replacement wheel is fitted.
Lug nuts can now be spun off quickly by hand or wrench, and snugged lightly against the wheel.
4
Lower the vehicle back onto the shop floor and use a calibrated torque wrench to tighten the lug nuts in a star or crisscross pattern.
The wheel is clamped securely with uniform clamping force.
Crisscross torquing prevents brake rotor warping and wheel hub misalignment.

Key Concept

Safe wheel removal and installation sequence
Estimated Time:45s
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Topics

Wheels and Tires

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