We are becoming increasingly concerned with contamination (particles and moisture) of equipment and the need to set cleanliness standards for our oils to achieve better equipment reliability. Whenever you send a hydraulic pump, motor, cylinder, power unit or even hose to a repair shop, there are many areas where contamination can enter your repairs and find its way back into your oil.
As part of establishing a quality lubrication program, you should consider the following:
Ensure the facility is organized, clean and well-maintained. A clean and organized repair shop is usually a contradiction of terms; however, it is crucial for clean repairs. Cleanliness and organization are an indication of a repair shop's efforts and habits. A well-organized, clean and impressive shop indicates a company that cares about its place of employment and its work. Clean facilities will be less likely to contaminate rebuild jobs. The dirt, dust and debris scattered around a dirty shop will find its way into repairs and back into your hydraulic oil, if care is not taken.
Tools such as lathes, drill presses, grinders, welders, torches and sandblasters should not be located in proximity of parts or repairs. Workbenches (where reassembly occurs) should be located as far from flying debris and equipment as possible. Some equipment uses cutting fluids and coolants that can also contaminate a repair, because they are usually water-based and latent with contamination.
Floor dry or kitty litter is messy and creates a lot of airborne dust which can get into repair work. When swept, floor dry becomes airborne dust and you don't want that inside any of your repairs. Absorbent pads and mats work better for spills and spill containment.
Every shop has a solvent tank of some kind for cleaning parts. Some shops even use multiple solvent tanks for primary and secondary parts cleaning. This is where repair parts will be cleaned for reassembly. To ensure the solvent tanks aren't another source of contamination, they should be filtered and cleaned on a regular basis. Ask about what type of solvent is used and how often it is serviced to make sure it's compatible with your equipment seal types.
Air tools simplify a mechanic's life, but exhaust ports on air tools blow air out, stirring up dust and debris. Shop air is also used to clean, dry or actuate components. Your repairs will come into direct contact with shop compressed air, as well as the dust that they stir up in the shop. That's why the repair shop must be clean and provide an air supply that is filtered, dried and lubricated.
Seals that have been sitting under fluorescent lights or are so dusty and dry they are cracked, are not ideal parts to be used in repairs. Seals have a limited shelf life, and storing them improperly shortens that life. The same approach applies to pumps, valves, cylinders and hoses. They should be sealed in bags or stored with the ports plugged or capped off. When you order a replacement pump, valve or some other part, you want it clean and ready for use.
Most shops use some form of lubricating oil or grease for holding seals in place during reassembly of repairs. Lubrication keeps seals from getting rolled or damaged when they are installed onto or into clean dry steel. That grease or lubricant should not be left open on shelves or workbenches where dirt particles can get into the oil or grease. Most shops use lubricants that are compatible with petroleum-based hydraulic oil; if you are concerned about compatibility, ask your repair shop what type of lubricants it uses.
Tools and Work Areas
Good housekeeping is not mandatory for a clean shop, but it is certainly a reflection of work habits. A mechanic's toolbox, and those of the company, reflect a work ethic and attention to detail. The workbenches and workspace where your repairs will be performed and tested should be clean and free from debris in that immediate area and the surrounding area. Areas for teardowns and inspections should be separated from repairs being reassembled. Work-in and work-out areas reduce potential contamination of repairs.
When hoses are made, they should be cleaned internally before hose ends are crimped on. This allows the crimped fitting to bond better with the hose. A quick blast of shop air is usually not a thorough cleaning process, but it's better than nothing. There is equipment that can shoot cleaning projectiles through the hose to remove more of the dirt inside the hose. In either case, ensure the inside of the hose is clean before you use it by visually inspecting it and shooting a projectile through if necessary.
Testing repairs usually validates a good or working repair, but if the oil in the repair company's test bench is not clean or compatible with your oil, the test could actually do more harm than good. Your repaired pump or cylinder could be heavily contaminated at this stage of a repair. Make sure your repair shop filters its test bench oil, takes regular oil samples of the oil, then make sure the oil is compatible with yours. Your oil cleanliness level is crucial to your quality lubrication program, and so is the oil at the repair facility because it too comes into direct contact with your equipment.
There are other areas or procedures that are important to your cleanliness program, so a trip to your repair facility is recommended. Conduct your own inspections, and indicate your preferences and standards both verbally and in writing. Most repair shops are proud to show off their facility and would welcome the opportunity to better meet your needs. Your time invested will reduce another external contamination source and will assist your efforts to better control the cleanliness levels of hydraulic and other lube oils.