How to Inspect Elevators for Hydraulic Leaks

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Some elevators use hydraulic oil to move the car up and hold it in place. The oil pressure is important for a safe and smoothly operating elevator. One of the most important jobs of an elevator service technician is to check for hydraulic leaks. A set of steps designed to catch visible and invisible leaks ensures elevator safety.

Inspect all hydraulic line couplings visually. The couplings connect pipes together and sometimes leak. Any wetness, puddles or dripping indicates a hydraulic oil leak.

Run the elevator down to the bottom floor and measure the oil level in the oil reservoir tank. At the bottom floor, the tank holds the most oil, so this is the most accurate representation of the amount available to run in the system at any given time, says elevator service technician Mark Dahlstrom.

Put a magnet right above the oil line in the reservoir tank to keep track of the amount. Then, repeat steps 1 and 2 a month later to determine if any oil is missing from the tank. It is important to measure the oil level when the elevator sits on the same floor each time.

Step into the elevator and run it up to any floor. Then, keep the elevator at that floor and wait about 5 minutes or so. If it slowly sinks and re-levels back to the floor, it could indicate a hydraulic leak. If the piston seal in the jack leaks, the return pump puts the oil right back in the system. The leaking and re-pumping causes the elevator to sink and re-level says Dahlstrom.


If you have evidence of a hydraulic leak, but cannot find the source of the leak, shut off the elevator immediately.


Only professional elevator technicians should perform regular maintenance and repair on these potentially dangerous machines.


  • Mark Dahlstrom; International Union of Elevator Constructors Service Technician; Cedar Rapids, Iowa