After the hydraulic cylinder has been used for a long time, it needs to be disassembled to check the status of each component.

such as observing the appearance of parts
(1) The inner surface of the cylinder;
(2) The sliding surface of the piston rod;
(3) sealing;
(4) The inner surface of the piston rod guide sleeve;
(5) The surface of the piston;
(6) Other parts vary depending on the structure and application. When checking, attention should be paid to whether there are cracks in the end cover, earrings, hinge shaft, thread on the top of the piston rod, and thread on the oil port.

Therefore, the inspection of hydraulic cylinder parts requires great patience and careful observation.

Now, we’ll start with the disassembly of the hydraulic cylinder.

How to Remove a Hydraulic Cylinder?

(1) First, the position of the piston should be moved to the top position suitable for disassembly by means of hydraulic pressure.

(2) Stop the hydraulic device from moving.

(3) In order to analyze the force of the hydraulic cylinder, in order to help find the cause of the fault and damage of the hydraulic cylinder. Before disassembling the hydraulic cylinder, the characteristics and installation orientation of the main parts, such as the cylinder, piston, guide sleeve, etc., should be marked.

(4) In order to remove the hydraulic cylinder from the drilling machine workbench, first remove the pipes of the inlet and outlet ports, and loosen all the connectors and mounting bolts at the end of the piston rod. When disassembling, it is necessary to prevent damage to the thread on the top of the piston rod, the thread of the oil port and the surface of the piston rod.

(5) Due to the different structure and size of the hydraulic cylinder, the disassembly sequence is slightly different. Generally, the fastening bolts or connecting rods of the end cover should be loosened first, and then the end cover, piston rod, piston, and cylinder should be disassembled in sequence. Be careful not to force them out of the cylinder when removing the piston and piston rod, so as not to damage the surface of the cylinder.

How to check the condition of the components after disassembly?

(1) Inner surface of the cylinder

Very shallow linear friction or point scars on the inner surface of the cylinder are allowed. However, if there are deep longitudinal scratches, even if the piston seal is replaced with a new one, it is impossible to prevent oil leakage. At this time, the inner hole must be ground, and it can also be corrected with very fine sandpaper or oil stone. When the longitudinal strain is a deep mark and cannot be corrected, the cylinder must be replaced with a new one.

(2) Sliding surface of the piston rod

When a longitudinal strain occurs on the sliding surface of the piston rod that slides relative to the piston rod sealing ring, the judgment and treatment methods are the same as those on the inner surface of the cylinder. However, the sliding surface of the sliding rod of the piston rod is generally hard chrome plated. If part of the coating is peeled off due to wear and vertical scars are formed, the oil leakage at the piston rod seal will have a great influence on the movement. The original coating must be removed, re-chrome-plated, and polished, and the thickness of the chrome plating is about 0.005mm.

(3) Sealing

Piston seals are key components to prevent oil leakage inside hydraulic cylinders. When checking the seal, first observe whether the lip of the seal is damaged or not, and the wear of the seal friction surface. When it is found that the lip of the seal is slightly scratched and the friction surface is slightly worn, it is best to replace the seal with a new one.

(4) Inner surface of the piston rod guide sleeve

If there is a scratch on the inner surface of the guide sleeve, it will not hinder its use. However, if the depth of uneven wear is 0.2~0.3mm, a new guide sleeve should be replaced.

(5) Piston surface

If there is a slight scratch on the surface of the piston, it will not affect the use. However, if the depth of the scar reaches 0.2~0.3mm, the piston should be replaced with a new one. In addition, it is also necessary to check whether there is a crack on the piston caused by end-face collision or internal pressure. The piston must be replaced if present, as cracks may cause internal oil leakage. In addition, it is necessary to check whether the sealing groove is damaged.

(6) Others

When inspecting, pay attention to whether there are cracks on the end face, earrings, and twisted shafts, whether there are any abnormalities in the thread on the top of the piston rod, whether there is any abnormality in the thread of the oil port, and whether there are cracks in the welding part.

In the end

In order to ensure safety, be careful when checking the components of the hydraulic cylinder. Many times, small negligence can cause huge losses. If conditions permit, it is best to find a professional to check. Professional workers can accurately judge what is wrong with the working status of the hydraulic cylinder.

For example, internal leakage, thrust, and speed drop may be due to the excessive gap between the cylinder bore and the piston, and the wear and tear of the seal on the piston. External leakage may be caused by worn piston rod seals and improper installation. Poor sealing of the cylinder head and increased external leakage may be due to roughening of the piston rod.

Many of the above problems require a lot of experience to discover. If you still have questions about hydraulic cylinders, please contact TorcStark, our professional technicians will provide you with the best solution.