HUB 3T7303 - Caterpillar

Values higher than the recommended target ISO code may require additional filtering of the oil.ISO 4406 Method for coding the level of contaminates by solid particles
ISO is a worldwide federation of national standards bodies. The ISO 4406 specifies the code to be used in defining the quantity of solid particles in the fluid. This ISO code is used in any given hydraulic fluid power system. An automatic particle counter derives the equivalent size of a particle from the particle cross sectional area. Particle counts are affected by various factors. These factors include: procurement of the sample, the sample container, particle counting accuracy, and the particle count cleanliness. Proper care should be taken during the sample procurement to ensure that the sample obtained is representative of the fluid circulating in the system.The code for contamination levels using automatic particle counters is composed of three scale numbers. Example X/Y/Z"X" - The number of particles that is equal to or larger than 4 microns."Y" - The number of particles that is equal to or larger than 6 microns."Z" - The number of particles that is equal or larger than 14 micronsAtthis timeCaterpillar does not require the reporting of the "X" scale number since the hydraulic tolerances exceed the 4 micron value, therefore a "-" is used in place of the "X". For example, a particle count is read as -/Y/Z, meaning that there was no requirement to count particles equal to or larger than 4 microns.Cleaning Procedure
Before service work is begun, park the machine on a hard level surface. Block the wheels of the machine so unexpected movement will not occur. Unexpected movement of the machine can cause personal injury or death.
Take an SOS oil sample and have the sample analyzed. A live oil-sampling valve is the recommended method to obtain the require oil sample. Refer to "Obtaining Oil Samples" and Contamination Control, PEGJ0045, "Reporting Particle Count by ISO Code" for additional information.
Inspect the hydraulic system (hoses, cylinders, and valves) for leaks. Most hydraulic oil contamination is brought into the system from an external source. Failure to make repairs before or immediately after filtration will not provide a long-term benefit.
Check the sight gauge and make sure that the hydraulic tank is filled to the full level.
DO NOT replace the machine filters at this time. New filters should be installed at the halfway point of filtration.Note: After one half hour of any kidney loop filtration, stop the procedure and change the machines hydraulic filter. This procedure will allow the new filters to assist in the system clean-up, but retain enough capacity to remain in place until the next scheduled filter change. This procedure also avoids opening the filter housing after the system has been cleaned, which can provide an inlet for contamination.Note: Only replace machine filters if scheduled to do so, or are not operating at optimal efficiency.
Start the filtered machine. Exercise the fluid system until the oil reached normal operating temperature. Shut off the machine.
Connect the filter cart to the machine.
Instructions