Hydraulic cylinders are much less complicated components than motors and pumps. This means that repairs are much easier to carry out on them. The amount of repair work that needs to be done depends on the extent of the damage or wear of the cylinder and the tools you have at your disposal. You should also take into consideration the cost of repairing the cylinder with the cost of replacing it with a new one. Here is some advice on how to conduct your own hydraulic cylinder repairs.
Disassemble and inspect
The most common form of damage is a leak to either the internal or external cylinder. By closely inspecting the cylinder parts, most importantly the seals, you will see what needs to be resolved. The pistol seal needs to be replaced if it is eroded, distorted or missing. This can happen because the piston bulges during its service or is simply too large. It is only a temporary fix to replace the seal and not the entire barrel, and therefore it will need replacement down the line.
You can check if there are any cracks in the rods by using a dye penetrant. If the chrome appears to be shiny on one side and dull on the other, the rod is bent. Bent rods can normally be straightened by using a press machine. However, sometimes the rod will not be able to withstand the pressure and crack as a result. This means that it will have to be replaced.
Check the barrel for any evidence of scarring or pitting. If this is the case, the effectiveness of the pistol seal will be greatly underwhelmed so the barrel will have to be replaced.
If there is only minor scoring on the cylinder's pistons, then this is not detrimental to the performance of the cylinder. If the scoring is substantial, the piston will need to be replaced.
You should always order seals directly from a supplier that specialises in seals, which means you don't have to measure the existing seals. Measuring seals is a tricky process as they can expand and contract during the use of the cylinder. To make sure the seal will fit, measure the grooves with a callipers.
Make sure that you clean all of the parts with a petrol based solvent before assembling the cylinder as well as drying it with compressed air. Make sure all of the seals are smooth and clean to ensure proper performance. Don't use sharp objects when conducting repairs on seals as they can nick them. Finally, plug the cylinder back into the service ports to prevent any dirt or debris entering it.