Hydraulic Oils; Correct Oil Leaks; Keep Hydraulic Oil Clean; Work Methods - Husqvarna ZTH5223 Workshop Manual

Hydraulic Oils

The oil is as important as any other part of the hydraulic system. It has been shown that 70% of all
problems with hydraulics are due either to the use of unsuitable oil grades or filling/topping-up with
contaminated oil.
Contamination from outside is responsible for by far the greater part of the impurities in the oil in hydraulic
systems.

Correct Oil Leaks

Cavitation from injested air can cause internal hydraulic pump and wheel motor damage. Air can enter the
system anywhere there is an oil leak. Therefore it is very important that oil leaks be repaired immedately.

Keep Hydraulic Oil Clean

Dirt and other forms of contamination are the greatest enemies of hydraulic systems. Long system life and
high efficiency very much depend on hydraulic oil being kept in good condition. Use only the grade of oil
stated in the lubrication chart. Make sure that hydraulic oil is inspected at regular intervals and that levels
are kept topped-up.
All high-quality hydraulic oils are supplied in clean containers and have been filtered as free from impurities
as possible. It is when the containers are opened or stored that problems arise. Do not open a container
before the area around the cap, seal or similar has been wiped clean of all dust, dirt, fibers and water. Any
other container, funnel or hose used when filling the hydraulic system must be clean.

Work Methods

Cleanliness is also vital for any components being removed from or fitted to a hydraulic system. However, it
must be borne in mind that used components sent to a workshop will often be specially inspected and/or
tested. Such components should be dispatched in the condition they were prior to removal. Otherwise, the
true reason for the fault may be difficult to ascertain and testing may give false results. Furthermore,
returned components that have been cleaned may mistakenly be presumed to be free from defect and sent
back without the appropriate action being taken.
The following are suggested as routine steps when working on hydraulic systems:
1. Perform general cleaning as necessary.
2. Protect the point/area where the repair is to be carried out from dust and other impurities in the air.
Plastic covers and the suchlike can be used.
3. Clean thoroughly using white spirit or an equivalent. It is not sufficient to clean only those parts
directly affected. Places from where dirt can fall onto the work point must also be cleaned. The
same applies to any tools used at the site of the intervention. Clean with a suitable brush, wipe
with a rag and repeat if necessary. Finally, spray the site, hose connections, etc. with clean white
spirit.
4. Fit suitable protector plugs/caps immediately after removing a hose or pipe. Components (even
those being replaced), hoses, pipes, etc. should all be suitably protected.
5. If they are not exchanged for new, all old pipe connector parts must be cleaned with fresh white
spirit and then blown with compressed air before refitting.
6. Maintain strict hygiene when measuring pressures. Before joining them, spray both parts of quick
couplings with white spirit. Ensure that any protective plugs/caps are clean before they are used
again.
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HYDRAULIC SYSTEM