How to Repair a Hydraulic Cylinder

Learning how to repair a hydraulic cylinder is not difficult. However, there are certain things you must keep in mind to ensure the cylinder is repaired correctly.
 

Types of Hydraulic Cylinders

There are two general types of hydraulic cylinders, and the repair processes will vary slightly depending on the type of cylinder you have.
 

Wire Ring

A wire ring cylinder has a wire ring that keeps the cylinder intact. After the ring is removed, then you can start to disassemble the cylinder to make the necessary repairs.
 

Threaded Head

A threaded head cylinder uses a set screw or locking ring and an end cap that screws onto the end of the cylinder to keep everything secure and in place. To remove the end cap, loosen the set screw or remove the locking ring. Then you are able to repair the cylinder. 
 

Types of Repairs and Maintenance Needed

Some of the more common reasons you need to repair and perform maintenance on cylinders include:

• Leaks – Before using the hydraulic system, the entire system should be carefully inspected for leaks, including cylinders. Cylinder leaks are the top reason for repairs.
• Worn Seals – Inspect the seals around the cylinder housing to verify they do not look damaged. However, internal seals are another matter. Seals wear out over time and eventually need to be replaced. So, seal replacement should be a regular part of your preventative maintenance plan.
• Worn Rods – Rods should last a long time with regular cylinder maintenance. However, if the seals are worn or the cylinders are not the correct size for the application, it can cause premature failure to the rods.  Problems like corrosion, pitting, and even bending can occur, requiring a new rod assembly.

Required Tools

There are specific parts, components, and tools you will need to repair your hydraulic cylinders as follows:

• New Seal Kit (O-Rings, Piston Seals, Wear Rings, Wear Bands, etc.)
• Rubber Mallet
• Punch
• Pliers
• Emery Cloth
• Torque Wrench
• Screwdriver
• Hydraulic Fluid
• Allen Wrench

Repair Processes

Whether you are repairing a wire ring or threaded head cylinder, you should follow specific repair processes to help reduce the risks of introducing contaminants into your hydraulic system.
 

Before

You will want to clean the exterior of the cylinder housing and remove all dust, dirt, grease, oil, and debris. You can use a petroleum-based solvent to help clean the cylinder. Once the cylinder is thoroughly cleaned, you can disconnect the hoses from the cylinder ports.

Make sure to plug the hoses and the port openings to prevent contamination. Next, disconnect the cylinder from the hydraulic equipment. Repairs should be made indoors in a location free from dust, dirt, and debris.

If you need to make repairs outdoors, you should take steps to erect a barrier around the repair area to reduce the risks of contamination.
 

During

While you are repairing the cylinder, you will want to clean every part and component using a petroleum-based solvent. In addition, you want to inspect piston rod seals and  O rings. Remember to discard the old ones and replace them with new rod piston seals and O rings.

You should also inspect inside the cylinder tube housing and look for metal to metal contact with the cylinder rod and housing. If you notice scratching, pitting, or other damages, such as the rod being bent or misaligned.

You will want to determine the cause of the cylinder failure and resolve the problem. Otherwise, it will only return repeatedly.  If you are doing cylinder maintenance, then inspect every part and component of the cylinder to identify potential problems you may need to resolve to prevent cylinder failure.

If you notice you need additional parts and components, you will want to get everything you need before reassembling the cylinder.
 

After

When reassembling the cylinder, remember to follow the steps in reverse order. You need to ensure every rod seal, piston ring, part, and component is in the proper location. For example, it is crucial to verify the internal wire is reinstalled in its proper position when repairing wire ring cylinders.

Most importantly, always follow the correct steps on how to repair and rebuild a hydraulic cylinder.
 

Hydraulic Cylinders and Parts

It is easy to find the hydraulic cylinders, parts, and components you need to repair and maintain your cylinders at White House Products, Ltd. We can also assist with repairs, custom rebuilds, and other hydraulic system parts needs.

Please feel free to browse our inventories online or contact us at +44 (0) 1475 742500 today!