Your Four Post Lift is a robust piece of machinery, but its safety and longevity rely on consistent, proactive maintenance. Among all routine tasks, checking and adjusting the cable tension is arguably the most critical. Improper tension can lead to premature wear, uneven lifting, and, most dangerously, increase the risk of component failure.
At Global Garage Supplies, we view proper cable maintenance as fundamental to workshop safety. Here is a technical guide for technicians on why cable tension matters and how to perform this crucial check.
Why Uneven Cable Tension is a Catastrophic Risk
The lifting cables on a four-post system synchronize the movement of the four corners and transfer the load from the hydraulic cylinder to the runways. They are designed to share the load equally during the lift cycle.
- Premature Wear: If one cable is tighter than the others, it carries a disproportionate amount of the load. This overload accelerates wear on that specific cable, its sheaves (pulleys), and the corresponding post components, drastically reducing the lift’s lifespan.
- Uneven Lifting: Unequal tension causes the lift to rise and descend unevenly, putting unnecessary torsional stress on the vehicle’s chassis and the lift’s structure. This stress can lead to permanent damage or component fatigue.
- Synchronization Failure: Poor tension can prevent the safety locks on all four posts from engaging simultaneously, leaving one corner potentially unsecured—a serious hazard.
Step-by-Step Cable Tension Inspection Guide
This check should be performed monthly, or after any instance where the lift was overloaded or used for heavy, concentrated repairs.
- Prepare the Lift: Lower the Four Post Lift completely until the runways are flat on the floor or the wheel stops. The runways must be empty of vehicles and accessories (such as Four Post Bridge Jacks).
- Inspect Visually: Check all cables for signs of wear, fraying, broken strands, or rust. A damaged cable must be replaced immediately—never reused.
- The ‘Pluck’ Test: With the cables relaxed, gently pluck each cable near the tensioning point. They should all produce a very similar sound and feel. If one cable feels noticeably tighter (higher pitch) or looser (lower pitch) than the others, it requires adjustment.
- Adjusting Tension: Using the provided tensioning nuts at the end of the cables (typically located under the runway or on the posts), loosen or tighten the cables one half-turn at a time. The goal is to achieve an even tension across all four cables. Always refer to your lift’s specific manufacturer manual for the exact procedure.
- Test Cycle: Raise the empty lift to its maximum height, then lower it onto the safety locks. Confirm all four locks engage audibly and simultaneously.
The Crucial Safety Protocol: Locks Over Cables
It is essential for every technician to remember that the lift cables are for lifting and lowering, not for holding the load during service or storage.
- Always Rely on Mechanical Locks: Once the vehicle is at the desired height, the Four Post Lift must be slightly lowered onto its mechanical safety locks. This ensures that the weight of the vehicle is supported by steel structure, not by the hydraulic pressure or the lifting cables. This protocol is the final safeguard against failure.
Ensuring correct cable tension is a simple yet vital task that protects your technicians and ensures your lift remains a reliable asset for years to come.
Download our Four-Post Lift Cable Maintenance Checklist to ensure compliance and keep your shop operating safely. Find more Vehicle Lift Essentials at Global Garage Supplies.