jcb JS300 Service Manual page 897

Contaminant Standards
Dirt that damages your system is in many cases too small
to be seen with the eye. The particle size is measured in
microns.
1 micron = 0.001 mm (0.0000394 in).
Listed below are a few typical comparisons:
– Red Blood Cell = 8 microns (0.008 mm, 0.000315 in)
– Human Hair = 70 microns (0.07 mm, 0.00275 in)
– Grain of Salt = 100 microns (0.1 mm, 0.00394 in)
Smallest particle visible to the naked eye is 40 microns
(0.00157) approximately.
Standards will often be quoted to ISO (International
Standards Organisation) for which literature can be
obtained.
Filters
The filter assembly fitted to all product ranges is designed
to filter all the contamination that is generated through use
to the required level of cleanliness. The filter must be
serviced to the requirements of the machine Service
Schedules.
To ensure optimum performance and reliability it is
important that the machines hydraulic system is serviced
periodically in accordance with the manufacturers
requirements.
E-236
Hydraulic System Fault Finding
9813/5100-1
Section E - Hydraulics
Hydraulic Contamination
E-236