Scissor jacks have become a vehicle-mounted tool for many vehicles because of their simple structure and portability. However, long-term use or improper operation may cause various faults, affect their performance and even bring safety hazards. This article will introduce the common faults, cause analysis and solutions of scissor jacks to help users maintain and use them correctly.

1. The jack cannot be raised or lowered or is difficult to raise

Possible causes

Rusty or lack of lubrication of the threaded screw: Long-term exposure to a humid environment causes metal parts to oxidize and get stuck.

Damage to internal gears or bearings: Overuse or overloading causes wear of the mechanical structure.

Improper operation: Not fully unlocked or the rocker is not inserted correctly.

Solution

Clean and lubricate the threaded screw: Spray the screw with WD-40 or a special lubricant and shake it repeatedly to loosen it.

Inspect the gear mechanism: If the internal gears are damaged, we recommend replacing the entire jack (as repair costs may be prohibitive).

Correct operation: Make sure the rocker is fully inserted and apply force steadily in the clockwise (up)/counterclockwise (down) direction.

2. The jack support is unstable or shaking

Possible causes

Uneven or soft ground: Use on sand, mud or slopes, resulting in uneven force on the jack.

Deformation of the jack base: Overload or impact causes the metal bracket to bend.

The vehicle is not fixed: The handbrake is not pulled or the wheel chock is used, and the vehicle moves and causes the jack to tilt.

Solution

Choose a solid and flat ground: It is best to operate on cement or asphalt roads, and use wooden boards to increase stability when necessary.

Inspect the base for deformation: If bending is detected, immediately replace the jack to prevent potential support failure.

Ensure the vehicle is stable: Tighten the handbrake and place wheel chocks on the diagonal wheels to prevent sliding.

3. The jack slides down automatically or cannot be locked

Possible causes

Self-locking mechanism failure: The internal ratchet or buckle is worn and the height cannot be fixed.

Overload: exceeding the rated load (such as using a 1.5-ton jack to lift an SUV), causing deformation of the mechanical structure.

Solution

Prevent overloading: Always select a jack with a rated capacity exceeding your vehicle's weight (typically 1.5-2 tons for sedans, 3+ tons for SUVs/trucks).

Check the self-locking device: If it cannot be locked, it may be that the internal parts are damaged. It is recommended to replace the jack with a new one.

Use with a bracket: After lifting the vehicle, be sure to use the jack bracket as a secondary support to prevent accidental sliding.

4. The rocker is broken or slipped

Possible reasons

Poor rocker material: The rocker of a low-quality jack may be made of fragile metal and easy to break.

Excessive operation: Excessive force or incorrect angle causes the rocker to twist or slip.

Solution

Replace a high-strength rocker: Choose an alloy steel rocker, or purchase original accessories for replacement.

Apply force steadily: Keep the force vertical when shaking to avoid lateral pulling.

5. Oil leakage from the jack (hydraulic scissor jack)

Some high-end scissor jacks use hydraulic auxiliary design, which may cause oil leakage.

Possible causes

Aging of the seal ring: Long-term use causes the oil seal to break.

Damage to the hydraulic cylinder: External impact or overpressure causes the cylinder to rupture.

Solution

Replace the seal ring: If the oil leakage is not serious, you can try to replace the O-ring.

Professional repair or replacement: The hydraulic system is more complicated to repair, it is recommended to contact the manufacturer or directly replace it.

Daily maintenance suggestions

• Regular lubrication: Use lubricant to maintain the threaded screw and movable joints every six months.

• Store in a dry place: Avoid humid environments to prevent rust.

• Check the load-bearing capacity: Do not overload, especially SUV/MPV requires a large-tonnage jack.

• Match with a safety bracket: After jacking up the vehicle, be sure to use the bracket to support it to avoid relying on the jack to bear the weight alone.

Summary

The main causes of failure of scissor jacks include insufficient lubrication, overload use, misoperation and natural aging of components. During the inspection and treatment process, it is recommended that cleaning and lubrication maintenance measures be first implemented. If structural damage or a significant decline in mechanical performance is found after inspection, it should be replaced professionally in a timely manner. It should be emphasized that in order to ensure the safety of the operation, it is strictly forbidden to perform vehicle bottom inspection work under the condition of relying solely on the jack to bear the weight. The safety bracket system must be used simultaneously to form a double protection mechanism.