Hydraulic Contamination - jcb JS300 Service Manual

Hydraulic Fluid Quality
This machine uses a large volume of fluid in the hydraulic
system for power transmission, equipment lubrication, rust
prevention and sealing. According to a survey conducted
by a pump manufacturer, seventy per cent of the causes of
problems in hydraulic equipment were attributable to
inadequate maintenance of the quality of the hydraulic
fluid. Therefore, it is obvious that control of the quality of
the hydraulic fluid helps prevent hydraulic equipment
problems and greatly improves safety and reliability.
Furthermore from an economic angle it extends the life of
the hydraulic fluid if quality is maintained.
Effects of Contamination
Once inside the system, hydraulic circuit contaminants
greatly effect the performance and life of hydraulic
equipment. For example, contaminants in a hydraulic
pump develop internal wear to cause internal leakage and
hence lower discharges. Wear particles generated will
circulate with the hydraulic fluid to cause further
deterioration in the performance of this and other
equipment. Contaminants also enter principal sliding
sections of the equipment causing temporary malfunction,
scuffing, sticking and leakage and can lead to major
problems.The main contaminants can be classified as
follows:
1 Solid Particles - sand, fibres, metallic particles,
welding scale, sealing materials and wear particles
etc.
2 Liquid - usually water and incompatible oils and
greases.
3 Gases - Air, sulphur dioxide etc. which can create
corrosive compounds if dissolved in the fluid.
These contaminants can appear during manufacture,
assembly and operation.
Cleaning Operation
The purpose of cleaning oil is to remove contaminants of
all types and sludge by filtering hydraulic fluid through a
K Fig 1. ( T
cleaning unit.
also refers.
E-235

Hydraulic Contamination

E-235). General Bulletin 011
Hydraulic System Fault Finding
TE-002_3
Procedure
Connect the cleaning unit in place of the hydraulic filter.
K Fig 1. ( T
E-235). Run the system for sufficient time to
pump all the hydraulic fluid through the unit. Disconnect
the cleaning unit and reconnect the filter. Top up the
system with clean hydraulic fluid as required.
9813/5100-1
Section E - Hydraulics
Hydraulic Contamination
Fig 1. Cleaning Unit
S168050-1
E-235