5.3.2
Hydraulic oil change
An oil change should take place about all 1500 - 2000 operation hours. Discharge and renew the
hydraulic fluid in condition at operating temperature.
The following table gives information on the state of the hydraulic fluid by simple visual inspection.
Finding
Dark colouring
Milky turbidity
Water separation
Air bubbles
Floating
contamination
or contamination
deposits
Smell of burn oil
WARNING!
Strongly aged hydraulic fluid cannot be improved by refill with fresh liquid!
Filling in of not filtered hydraulic oil can lead to malfunctioning or to premature
loss of valve components!
NOTE!
i
Use only filtered hydraulic oils (5 µm), which fulfil the minimum requirements to
hydraulic oils of the type HLP 46 according to DIN 51524 part 2.
Contamination
Oxidation products
Water or foam
Water
Air
Solig foreign material
Ageing products
- 51 -
Possible cause
Overheating, neglected oil change
Water and air penetration
Water penetration, e.g. coolant
Air penetration, e.g. as result of oil deficiency or
leaky suction pipe
Abrasion, dirt, ageing product
Overheating