Hydraulic cylinders are an essential component for a wide variety of industrial sectors. They are intrinsic to the operation of hydraulic presses, cranes, agricultural vehicles, excavators, hydroelectric stations, conveyor belts and shipbuilding machinery to name just a few.
The usefulness of hydraulic cylinders means that they are ubiquitous across a number of sectors and industries. They have become a driving force for the construction and destruction industries and, as such, it can be a real blow when they break or malfunction. Unless you’re clued up, a hydraulic cylinder in disrepair can spell a significant loss of time and money. So, with that in mind, here is some industry knowledge on how to repair hydraulic cylinders.
Things to Check First
First of all, it’s imperative to know what’s wrong before you can make repairs. With that in mind, it’s worth identifying the issue through some simple troubleshooting. The good news is that most problems with hydraulic cylinders are easy to fix because of how well engineered they generally are.
If you’ve noticed that you’re having trouble raising or lowering your hydraulic system, here are some things to check:
The hoses. Ensure that all hoses are connected correctly and that the couplings engage.
Check the pump. It may be the case the oil in the system is too low or too full.
Double check the weight you’re lifting. It may be over-capacity for the system.
Check for damaged seals.
Double check any release values are in the correct positions
Before disassembling your hydraulic cylinder, it’s crucial to identify the type of cylinder you’re working with, as there are a number of different varieties for different functions. You can find identifying numbers on the end cap of the cylinder. It’s also a good idea to find any diagrams or instructions that came with the cylinder and it’s imperative to use jacks to prop up cylinder when making repairs to keep you out of harm’s way.
To disassemble the cylinder, you’ll have to use a gland removal tool. Firstly, ensure that there is no pressure within the cylinder by loosening the hydraulic lines to let it escape. Then, using the tool, remove the gland and unscrew it from the cylinder to gain access to the piston rod.
When removing the piston rod, make a special effort to ensure that it doesn’t fall on the ground or get damaged on other pieces of metal machinery, as this can have dire consequences for the component. When the piston rod is free, unscrew the bolt which connects the piston from the rod.
When disassembling the piston and removing all seals and o rings, keep a close eye out for misconnected parts, as this could well have been the cause of a leak and malfunction. You should also look out for signs of rust and excessive dirt and, if you find any, use some sandpaper, a cloth or, preferably, an electric polisher to remove it.
During the reassembly of the cylinder and its components, replace the used seals with new seals and o rings to improve the lifetime of the hydraulic cylinder after the repair. Make sure that you are doing this very carefully and in the right order so that no further gaps occur.
Before putting the piston – reattached to the rod – back into the cylinder, check the inside of the cylinder for scars or damage, as this can cause further damage to the piston rod. If you find some, you may need to replace the cylinder. Once you’ve found that there are no internal scars in the cylinder, liberally grease the inside and place the piston rod back in.
Repairing a hose
If the problem is not with the cylinder and piston, but with the connecting hose then there are a few steps you can take to make a repair.
Firstly, it’s important to identify the hose that needs repairing. Keep an eye out for scarring, holes or any other damage to the hose.
Once you’ve identified the hose that needs to be repaired, cut out the damaged area and clean around the cut so there is no dust or dirt.
Check that the length of the new hose matches, ensure it is properly rooted, use an adapter to complete the installation and make sure all couplings are tightened properly.
Double check that all seals are flush and there are no gaps
Circulate the fluid at low pressure and watch out for leaks. Run the system for a few minutes and keep checking for leaks with a piece of cardboard.