The disassembly of hydraulic cylinders is a process that requires careful operation and involves multiple steps and precautions. To ensure the safety and efficiency of the disassembly and assembly process, it is necessary to follow the correct steps.

01

Disassembly preparation

2. Get tools ready

Prepare the necessary tools, cleaning agent, lubricating oil, marker, rags, brushes and oil pan (for waste liquid, cleaning agent, lubricating oil). Before disassembly, check the appearance of the hydraulic cylinder to see if there is wear and rust, so that you can perform targeted operations during disassembly.

3. Clean the hydraulic cylinder

Before disassembling the hydraulic cylinder, clean the dirt on the surface of the cylinder to prevent it from entering the cylinder and affecting its use. At the same time, ensure that the working area is clean and tidy. This is not only conducive to maintaining the hygiene of the machine, but also reduces the interference of oil and dust.

02

Disassembly steps

1.Remove the joints on the oil inlet and outlet, and then drain the oil in the cylinder to prevent oil from flowing out during disassembly.

2.Disassembly of the connection

Use a wrench or screwdriver to separate the pipes and connectors from the hydraulic cylinder. Be careful not to hit the machine directly with a hammer to avoid damage.

3.Disassemble the end cover: Use appropriate tools to disassemble the end cover. Be careful not to damage the end cover and gasket, and avoid damaging the cylinder or other components during the disassembly process.

4.Disassemble the piston rod: Remove the piston rod from the cylinder. If necessary, remove the sealing ring and O-ring in the front and rear directions of the piston rod.

5.Separate the piston: Remove the piston from the cylinder. If there is a tight connection between the piston and the cylinder, choose an appropriate loosening method based on the working conditions, such as using a handwheel, hammer, etc.

6.Disassembling the cylinder body: If the cylinder body needs to be removed, you can use a disassembler to remove the cylinder body.

7.Remove the seals, O-rings and other small parts inside the cylinder.

03

Disassembly precautions

1.Before disassembly, the hydraulic circuit should be depressurized. Otherwise, when the oil pipe joint connected to the oil cylinder is loosened, the high-pressure oil in the circuit will spray out quickly. When depressurizing the hydraulic circuit, first loosen the handwheel or pressure regulating screw at the overflow valve to unload the pressure oil, then cut off the power supply or power source to stop the hydraulic device.

2.When disassembling, avoid damaging the piston rod top thread, oil port thread, piston rod surface, cylinder sleeve inner wall, etc. In order to prevent the piston rod and other slender parts from bending or deformation, use wooden blocks to support them evenly when placing them.

3.Complete the disassembly in order. The disassembly order of various hydraulic cylinders is slightly different due to their different structures and sizes. However, it is generally necessary to disassemble them in the order of draining the oil, removing the cylinder head, and removing the piston or piston rod.

When removing the cylinder head, special tools must be used for the keys or snap rings of the internal snap-on connection, and flat shovels are prohibited; flange-type end covers must be pushed out with screws, and hammering or hard prying is not allowed. When the piston and piston rod are difficult to pull out, find out the reason before disassembling, and do not force them out.

4.Before and after disassembly, prevent the parts of the hydraulic cylinder from being contaminated by surrounding dust and impurities. Disassembly should be carried out in a clean environment as much as possible. Cover all parts with plastic cloth after disassembly.

5.After disassembly, carefully inspect to determine which parts can continue to be used, can be reused after repair, and must be replaced.

6.All parts must be cleaned carefully before reassembly.

7.Correctly install the sealing devices in various places:

*When installing an O-ring, do not expand/expand it to the state of permanent deformation and do not roll while assembling it; otherwise, it may get twisted and result in oil leakage.

*When installing Y-shaped and V-shaped sealing rings, pay attention to their installation direction to avoid oil leakage due to reverse installation. The lip of the Y-shaped sealing ring should face the oil chamber with pressure, and pay attention to distinguish whether it is for the shaft or the hole. The V-shaped sealing ring is composed of a supporting ring, a sealing ring and a pressure ring of different shapes. When the pressure ring presses the sealing ring, the supporting ring can make the sealing ring produce a shape to play a sealing role. When installing, the opening of the sealing ring should face the pressure oil chamber; when adjusting the pressure ring, it should be limited to no oil leakage, and it should not be pressed too tight to prevent excessive sealing resistance.

*If the sealing device is matched with the sliding surface, an appropriate amount of hydraulic oil should be applied during assembly.

*All O-rings and dust rings should be replaced after disassembly.

8.After the piston and piston rod are assembled, measure their coaxiality and straightness over the entire length to see if they are out of tolerance.

9.After assembly, there should be no sense of obstruction or uneven resistance when the piston assembly moves.

10.When the hydraulic cylinder is installed on the main engine, sealing rings must be added between the inlet and outlet joints and tightened to prevent oil leakage.

11.After assembly as required, several reciprocating movements should be performed under low pressure to expel the gas in the cylinder.

Article from JW HYDRAULIC，Sale manager: Nancy  Zhu

Email: nancy@jwgroup.cc Mobile/Whatsapp:+86 15902166721

HYDRAULIC CYLINDER specialist of hydraulic cylinder and CNC machinery parts

JW GROUP is an integrated steel product group,subsidiary JW STEEL/JW HYDRAULIC products include:hydraulic cylinder, hydraulic cylinder spare parts,drilling forging parts, pneumatic actuator-scotch yoke, machinery part.