Repairing Hydraulic Cylinders for Effective Performance

Comparatively, hydraulic cylinders are less compicated than other hydraulic components and hence easy to repair. In most cases, the user carries out the repairing work of hydraulic cylinders on his own. Ofcourse, to what extent the repair work can be done in-house depends on the extent of tear and wear of the cylinder and how well-equipped the user is wih the required tools. Morover, a lot depends on the expenses involved. We present below a guide on how to go about the hydraulic cylinders repairing on your own:

Disassembly and Inspection

One of the common problems in hydraulic cylinder is leakage. So whenever there is a problem in the cylinder, it is necessary to disassemble it, and closely observe any external or internal leakage in the cylinder parts.

Piston Seal

If the piston seal is missing or distorted, or the barrel is not of the proper size or has become bulged after use, then it is necessary to replace the barrel or the complete cylinder. It is no point replacing the piston seal without replacing the barrel, as it will give a short-term life.

Rod Seal

Check the rod seal. If the rod seal is badly distorted, then replace it. There is no need to repair the rod seal as it wont give a long service life.

Rod

You also need to check the rod. Check for cracks at all points where its cross-section changes. You do this by using dye penetrant. Observe the chrome surface of the rod. If it looks dull on one side and polished on the opposite side, it means that the rod is bent. You also need to check the straightness of rod when you go for repairing a cylinder. This is done by placing the rod on rollers and measuring the run-out with a dial gauge. Place the rod in such a way that the distance between the rollers (L) is as large as possible. Now measure the run-out at the middle point between the rollers (L/2). Use a press to straighten bent rods. If the chrome is damaged, then the rod must be either rechromed or replaced.

Barrel

Inspect the barrel. There might be internal pitting or scoring. If the barrel is scored or pitted, the service life of the piston seal will be reduced. Therefore, the barrel must be repaired or replaced.

Piston

Check the pistons of the cylinders. As it is made of aluminum alloy or cast iron, there is chances of scratches, scores in the piston. Minor scoring on the outside of the piston does not affect the functioning of the cylinder, so long the minimum diameter of the piston is not less than the nominal bore diameter minus 0.006 inch. This checking is done using an external micrometer. If the piston diameter measures outside this tolerance, then it should be replaced by a new piston , but made from a similar material.

Seals Ordering

If seals need to be replaced, dont measure the old seals. Seals can shrink or swell in service. It can also be that an incorrect seal may have been installed earlier. So when you order for seals from your supplier, use a vernier caliper to measure all seal grooves.

Assembly

For the last step, that is assembling the hydraulic cylinder parts, use petroleum-based solvent to clean all parts and blow-dry using compressed air. Use clean hydraulic fluid during assembly. Avoid using a screwdriver when installing seals. Before installing seals, make sure that the seal grooves are clean and free from duct, nicks and burrs. After the hydraulic cylinder has been assembled, plug its service ports to avoid ingress of dirt or moisture.