Bleed air from the cylinder is a very important regular maintenance job of a dump truck.Trapped air inside can waste the hydraulic fluid of the system.This will lead to problems such as performance degradation, component damage, cavitation,etc.It may even cause the cylinder to shut down completely.

You can extend the service life of the dump truck cylinder by bleeding air from the cylinder.Keeping cylinder clean over the long term can reduce downtime at the same time.The steps of bleeding air from dump truck cylinder are easy.Just follow the steps below you can easily operate.

Timing to Bleed

Before you bleeding air from the dump truck cylinder,you must know the timing when you need to bleed air.Beside the regular maintenance,there are few other problems when you need to bleed air too.The following situations indicate that it’s the timing to bleed air from the dump truck cylinder：

1.Before Installing the Cylinder or After Maintenance

Before installing or repairing the cylinder, it is necessary to bleed air from the cylinder. There is a vent valve at the top of the hydraulic cylinder to release air during the running of the cylinder. If there is air in the system, it will form a gas shock absorber effect.That will cause damage to the sealing component and blow them out of the cylinder body.

2.Knocking Noises from Cylinder

If you hear a knocking or banging sound in your cylinder system, that means there is air in the cylinder.The noise is caused by the compression and expansion of air. Check the hydraulic cylinder and pump for signs of air leaks and check for damaged seals.

3.Hydraulic Fluid has Deteriorated

Normal hydraulic fluid is clear and transparent, yellow or amber in color. If you find that the hydraulic fluid has darkened or turned black, has sediment.Or has a pungent odor, it means that the hydraulic fluid has deteriorated.

Deteriorated hydraulic fluid can cause air to enter the hydraulic system, leading to unstable pressure and cylinder crawling. In this case, the cylinder needs to be bleeded.

4.Sealing Parts are Replaced or Damaged

Typically, after a seal is replaced or damaged, the fluid circuit’s sealing performance deteriorates, allowing air to enter the system. If the air is not promptly bleeded, it can lead to problems such as abnormal pressure, unstable operation, hydraulic fluid leakage etc.

5.When Replacing or Replenishing Hydraulic Fluid

When replacing or replenishing hydraulic fluid, air may be mixed into the new oil. That will cause unstable fluid pressure. This may lead to cavitation, causing hydraulic components to vibrate and generate noise. Even damage the sealed metal parts.

Operate Steps of Bleeding Air

The principle of cylinder exhaust in dump trucks is roughly to raise air to the top of the oil cylinder to release it, but the specific operating steps vary depending on the cylinder design.

In recent years, many dump truck consumers choose bleederless cylinder designs. However, older cylinders may still be equipped with air bleeded valves, which require manual bleeding for maintenance. The following contents will introduce the bleeding methods for both cylinder designs.

1.With Air Bleeded Valve Design

Hydraulic cylinders with air bleeded valve designs are fewer and fewer on the market. Replaced by designs without air bleeded valves. If your dump truck cylinder is equipped with an air bleeded valve, the bleed process can be completed in just 4 steps.

Step 1

Raise the cylinder and dump the body to fully extend. Maintain this position for a few minutes to allow air to move to the top of the cylinder.

Step 2

Lower the cylinder and dump truck body.Keep the distance of approximately 2 feet between the dump body and the chassis frame. Make the dump truck body up level in the center position.

Step 3

Open the cylinder air bleeder valve control device and wait for all trapped air to be bleeded.

Step 4

When a large amount of hydraulic fluid flows out of the air bleeder valve, close the air bleeded valve. Air bleeding is complete.

2.No Air Bleeded Valve Design

This is currently the most popular cylinder design. No air bleeded valve design does not have traditional air bleeded valves, but instead uses closed pistons during installation to prevent air retention. Here are the 3 steps for bleeding air:

Step 1

First, install the hydraulic cylinder on the dump truck.

Step 2

Then connect the cylinder to your system. Complete 2 to 3 full extension and retraction cycles to bleed any trapped air.

Step 3

Last,if there is still trapped air, repeat the extension and retraction cycles 2 to 3 times as needed.

Attention

1. Keep the system stationary during bleeding. Ensure the safety of bleeding operations and prevent accidents.
2. Pay attention to the position of the bleeding port. Prevent air splashes from causing injury to people or damage to other equipment.
3. Ensure that the bleeding port is properly sealed to prevent air from re-entering the system.

Conclusion

It is very important to regularly bleed the air from the dump truck cylinder. This can help you avoid many potential problems. Save the repair costs in the meanwhile. If the above steps can not solve your problems or you have other concerns. Please contact Target’s technical department, where professional engineers will help you resolve the issue.