Troubleshooting: Humming Noise During the Upward Movement of a Guide Rail Lift

After a guide rail lift was installed and commissioned, our customer noticed a humming or “woo-woo” noise while the platform was moving upward.

Based on the symptoms and our troubleshooting experience, we determined that the noise was most likely coming from the hydraulic cylinder, particularly from the piston rod moving through its sealing system.

What Can Cause This Noise?

Several factors can contribute to this type of noise:

• The two hydraulic cylinders may not be perfectly parallel.

• The piston rod may have relatively tight contact with the sealing components.

• The cylinder seals may be new and relatively tight after installation.

• The alignment of the cylinder and lifting structure may create additional friction during movement.

When the lift is newly installed, these conditions can sometimes produce noticeable friction noise during the upward movement.

Our Recommended Solutions

We recommended two simple measures to the customer.

1. Lubricate the piston rods

The customer was asked to apply a small amount of suitable lubricating oil to the exposed piston rods. Ordinary mechanical/engine oil can be used for this purpose, provided it is compatible with the equipment and kept away from areas where contamination could cause problems.

This helps reduce friction between the piston rod and the sealing components during the running-in period.

2. Add lubricating oil to the hydraulic system

We also recommended adding approximately 10 liters of suitable hydraulic oil to the hydraulic oil tank, according to the system's oil capacity and specification.

After the initial adjustment, the noise did not disappear immediately. However, after the lift had operated for several days, the customer reported that the noise had become significantly quieter. The customer then added several more liters of hydraulic oil as part of the ongoing adjustment.

What Happened After Running the Lift?

This case demonstrates an important point when commissioning a newly installed hydraulic guide rail lift.

New cylinder seals can initially be relatively tight against the piston rod. As the cylinder operates over time, the sealing and sliding surfaces gradually run in, reducing friction and making the movement smoother and quieter.

At the same time, cylinder alignment should always be checked carefully. When a lift uses two cylinders, keeping the cylinders properly aligned and parallel is important for smooth operation and can help prevent unnecessary side loading and friction.

Troubleshooting Summary

If a newly installed guide rail lift produces a humming noise during upward movement, we recommend checking:

1. Cylinder alignment – make sure the two cylinders are properly aligned and parallel.

2. Piston rod condition – check whether the piston rod is clean and moving smoothly.

3. Cylinder seals – new seals may initially create higher friction.

4. Lubrication – use appropriate lubrication to reduce friction where applicable.

5. Running-in period – allow the hydraulic cylinders and seals to operate for a period of time and monitor whether the noise decreases.

In this particular case, the noise became much quieter after several days of operation. This indicates that the cylinder sealing system was gradually running in and the friction was decreasing.

The key lesson: Not every unusual hydraulic noise means that a cylinder needs to be replaced. Correct alignment, appropriate lubrication, and a proper running-in period can often make a significant difference.

For more technical cases like this, visit our Troubleshooting Blog.