21528 Mercury NUT, POWERHEAD STUDS (5/16-24)

Measuring Cleanliness
Fluid cleanliness can be measured by taking fluid samples from various machine compartments. Your Cat dealer can analyze the samples. Particle contaminants are typically measured by particle counters. Chemical contaminants can be measured by specific analysis techniques such as oxidation, water, or soot tests. Some chemical contaminants, such as water in fuel, can interfere with the particle counters and can be counted as particles. Refer to your Cat S O S lab or to your Cat dealer for more information.The number of particles in fluids is expressed in "ISO (International Organization for Standardization)" ratings. "ISO 4406" Standard classifies fluid cleanliness by the number and size of particles in 1 milliliter of fluid. "ISO 4406" Standard measures particle size in µm (microns) and reports the resulting count in three code ranges X, Y & Z. The three code range defines the size and distribution of particles in 1 milliliter of fluid:
The first code range, X represents the number of particles equal to or larger than 4 µm per milliliter of fluid.
The second code range, Y represents the number of particles equal to or larger than 6 µm per milliliter of fluid.
The third code range, Z represents the number of particles equal to or larger than 14 µm per milliliter of fluid.An example of an "ISO 4406" particle count is 18/16/13. Cat "ISO" cleanliness recommendations are expressed as two or three codes, depending on the machine system. The three code range follows "ISO 4406" definitions and is used for liquid fuels such as diesel and gasoline. The two code system, example "ISO -/16/13", is used for certain lubricant systems. In the two code system, the first number is the number of particles equal to or larger than 4 µm per milliliter of fluid. This number is not required and may be represented by a dash (-). The second number (Y) and the third number (Z) follow "ISO 4406" definitions. Cat reports the Y and Z codes for lubricating oils to keep consistency with older data and reports.An example of the particle size and distribution of the "ISO 4406" codes is given in Table 1.
Table 1
ISO 4406 Code Number of particles in 1 milliliter of fluid
4µm and up 6µm and up 14µm and up
"ISO 18/16/13" 1300 - 2500 320 - 640 40 - 80
"ISO 21/19/17" 10000 - 20000 2500 - 5000 80 - 160 Note: Several factors affect the results of particle counts. The factors include the cleanliness of the equipment used to obtain the sample, sample techniques, the cleanliness, and type of sample container, particle counter accuracy (calibration, maintenance, and process), and the environment where the sample is procured. Samples should be taken at representative locations in the fluid circulation system or the fluid distribution system when possible. The sample should be protected adequately from contamination during transport to the lab for analysis.In addition, particle counters may count water droplets and air bubbles as particulate contamination.Note: American Society for Testing and Measurement has developed "ASTM D7619" “Standard Test Method for Sizing and Counting Particles in Light and Middle Distillate Fuels, by Automatic Particle Counter”. This test procedure was developed in 2010 to count and measure the size of dispersed dirt particles, water droplets, and other particles in 1-D and 2-D diesel fuels when the specified particle counter is used. "ASTM D7619" is also applicable to biodiesel fuels.Cleanliness Standards for Machine Systems
Cat recommends that machine systems be maintained at the factory defined fluid cleanliness targets.Cat has established minimum fluid cleanliness targets for fuels and fill oils and for machine roll-off. Fluids filled into the machine or engine fill tanks are recommended to be at the target levels provided in Table 2 or cleaner. Cleanliness targets for applicable machine component systems are referred to as “Roll-off”. Roll-off is defined as the cleanliness specification of the fluid that is to be obtained before the machine returns to work after maintenance and or system invasion repair. When system fill fluids and Roll-off are maintained at or cleaner than the "ISO" cleanliness targets, contamination-related effects will be reduced.
Table 2
Cat Recommended Fluid Cleanliness Targets(1)
Cat Recommended Cleanliness Targets for Fluids Dispensed into Machine or Engine Fill tanks Fill oils(2)(3) ISO -/16/13
Dispensed fuels ISO 18/16/13
Dispensed DEF ISO 18/16/13
Cat Recommended Machine Roll-off Cleanliness Targets Hydraulic systems (Implement & Steering) ISO -/18/15
Electronic Transmissions ISO -/18/15
Mechanical Transmissions ISO -/21/17
Differentials, Wheels, and Axles(4) ISO -/18/15
(1) The fluids should meet or exceed the cleanliness requirements of the listed ISO levels.
(2) For engine oils optical particle counters may not be effective. Instead filter the oil prior to dispensing into the engine tank, use engine oil filters of 12 micron absolute efficiency and ensure that the oil temperature is 20° C (68° F) or higher. Refer to the details given in this article.
(3) For transmission, gear, differential and axle oils, additives and the viscosity of the oil may interfere with particle counting. An alternative is to use adequate filtration to ensure clean oils prior to filling in the machine compartment.
(4) This cleanliness standard applies only to the Series 700 family of rigid frame trucks, 777 size