Farms and heavy equipment use hydraulic pumps, spool valves and cylinders to do their jobs. These components are interconnected with a series of steel tubes and rubber reinforcement sleeves. Sometimes lubricating oil can leak out of the sleeves, making it necessary to replace them. It's a bit of a dirty job, but doing it yourself will save you time and money.
Steps
Step 1. Find the sleeve causing the problems
This will be evident if the sleeve has exploded, which can happen since the oil is pumped even at over 140 atmospheres of pressure, and an explosion can cause a large quantity to be lost in a short time. But if it's a small leak, just look at where the oil is dripping, and follow the trail of liquid that will lead you to the source. Never use your hands or other parts of the body to discover the loss. Use cardboard, paper, or fluid to find hydraulic leaks so that no further oil leaks occur. A good plumbing shop provides additives to find leaks that help effectively and safely.
Step 2. Evaluate how many components to remove to facilitate replacement of the damaged sleeve
Always label removed components with numbers and letters so you can easily reassemble them after replacing the components. The pieces to be removed can include cases, guards, clamps, other sleeves, hydraulic cylinders and more. Follow the sleeve from one end to the other, remembering the path to follow to uninstall and reinstall it, after putting the numbers and letters on the openings and ends of the sleeve.
Step 3. Decide if the hydraulic component that the sleeve protects is efficient, or if any other hydraulic component to be removed still has an "unexploded load", or a weight on them
If the oil in the system you are disconnecting is under pressure, it may expand strongly when the connections securing it are loosened, causing the oil to drain under pressure. Before proceeding, it measures the pressure in the cylinders and components.
Step 4. Make sure that each connection supported by the hydraulic cylinder, which the sleeve protects, is grounded, blocked or secured
The weight of the connection could break a mechanical component if it suddenly falls, when the pressure of the cylinder supporting it is detected.
Step 5. Get the tools you need to do the sleeve removal job
The implants on each end of the sleeve will need to be removed with a wrench, which will vary in size based on the attachments. Many of these implants are designed to rotate as they work, so it will take two wrenches to remove each of them. Hold the fixed side of the pair with a wrench to prevent it from turning and damaging the ring as you turn the other side to separate the pair.
Step 6. Remove all clamps and connections that interfere with the removed sleeves
Often, the same hydraulic cylinder will have to be removed or supported in order to have access to the systems. The hydraulic cylinders are bolted directly to the main part or structure they are working on, or they are anchored to a steel pin, as in the illustration.
Step 7. Loosen the connections that bind the hydraulic hose to the system, torque, cylinder or spool valve
Make sure the implants turn on the threaded connections, in order to hold the other connections, the ones to which the sleeve is attached, with a separate wrench.
Step 8. Pull the sleeve away from the system when both ends are detached
Watch out for any oil leaks; maybe keep a bucket handy to collect it.
Step 9. Close the remaining brackets in the machine to prevent debris from falling into the system while the other brackets are open
If you don't have oil leaks from your systems and you don't have a plug with the right thread, you can tie a clean rag around the connections to protect them, but be careful if rain is expected, as a rag will not protect the system from water.
Step 10. Remove excess oil from the sleeve and take it to a store to get a new one
Many manufacturers supply replacement sleeves and connections that can be mounted on site, all of which are less expensive than the original products. Make sure the shop that manufactured the cuffs cleaned them inside with a suitable cleaning system, not just compressed air. Some stores use advanced systems and install end caps to prevent the system from being contaminated from the outside. The caps will keep the line clean until it is inserted into the system and installed permanently.
Step 11. Clean all system connections before reinstalling the cuff
Make sure there is no dirt in the pipes and connections that can then end up in the plumbing system once the job is done.
Step 12. Plug the ends of the new cuff with a special cover or clean cloth before inserting it into the system
This will keep it protected from debris that can enter while you install it. Remove this temporary cover just before installing the connections where they meet the equivalent component on the other side.
Step 13. Make sure the sleeve is placed in the right space and has the right "play" where needed, then screw the connections back onto the cylinder or component they were removed from
Tighten these connections carefully. You may have access to specific instructions that will suggest you add a torque necklace to each connection, but if you don't have these components, just tighten the connections as best you can, without risking damaging the gaskets or marking the thread that holds them together.
Step 14. Replace the clamp, shroud, and other components that were removed to accomplish the task
Line up any cylinder pins that were removed and reinstall them, replacing any o-rings needed to secure them.
Step 15. Check the fluid level in the machine, increase it and check for any leaks
If you've had a chance to clean any surfaces that got dirty with the initial leaks, any new leaks will be easier to spot. Remember that some hydraulic circuits require a purge to remove air from the system before using the machine. This is usually done on the drive and brake systems, but there are other situations where air can be trapped, such as in a "single action" cylinder where the power is at its lowest level.
Advice
- Inspect any equipment before using it. Industrial inspections are carried out every day or at the beginning of each change. Check for oil leaks, visible damage, or other signs of inefficient systems.
- The safest method of checking for leaks from small holes while the system is under pressure is to simply use a sheet of paper held close to the sleeves. The point of the leak will be easily identified.
- Reinstall any damaged sleeves or scuffs that cables or braided wires may show. Never bring any part of the body close to hydraulic hoses, connections or pipes as any external pressure can cause damage and oil leaks. Add this to routine maintenance, instead of waiting for catastrophic damage, which can cause at least damage to other parts of the machine, but also injury to people or even death.
- Store the bolts, supports, and rings in a container until you need to reinstall them.
- Clean all surfaces you will need to access while working, if possible, to make operations easier and cleaner.
- Mark each component where it will be difficult to find the right location, especially if you have to remove many sleeves, so as not to reinstall them in the wrong spaces.
- Make sure you find the right sleeve to fix it. The sleeves are often grouped together in a small space, which makes it difficult to locate the leak.
- Make sure you have all the tools you need before starting the job.
Warnings
- Hydraulic oil under pressure can be introduced directly into human skin tissue and can cause serious damage. In particular, hand injuries can be deceptive and appear benign because all in all they are marked by minor injuries. In fact, all hand injuries require immediate and careful exploration by a surgeon, due to the many tissues involved.
- Hydraulic hoses have steel cables or coiled casing structures underneath the outer cover, and when these are exposed and scraped, they can cause nasty cuts and abrasions.
- Hydraulic oils can be flammable, so any leaks need to be addressed immediately upon discovery.
- Hydraulic components can weigh up to tens of kilograms, so be careful when dealing with them.
- Make sure the hydraulic hose is put back in place with the same or higher degree of pressure, and that the fluid used is an organophosphate or synthetic mixture. Make sure the replaced hose meets the suction line and pressure requirements.
