Service Information
Document Title:
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Information Type:
Date:
Safety
for
work
on
hydraulic systems
191
Service Information
2014/3/20
Profile:
BHL, BL70 [GB]
Safety for work on hydraulic systems
The hydraulic systems in our backhoe loaders work at very high pressures, up to approx. 35 MPa (350 bar) (5075
psi). In order to prevent serious personal injuries, it's important that the systems are maintained correctly and that
all persons who come into contact with the machines are very careful and very alert to any defects.
Those who follow the simple rules below have laid a good foundation for accident prevention.
General
Never adjust a pressure limiting valve to a higher pressure than that recommended by the manufacturer.
A hydraulic hose that swells, for example, at a connection, indicates that it's about to burst. Replace the hose as
soon as possible! Pay attention to leaks from hydraulic hoses and connections. Repair the leakage before the part
bursts!
Scrapped accumulators must be punctured before they are discarded to prevent explosions. Carefully drill a hole
with a 3 mm (0.12 in) drill bit.
WARNING
If the pressure is not released before opening the system, oil under high pressure will jet out, resulting in serious
personal injuries.
Pressure release
When the engine has been stopped, there remains an accumulated pressure in the system. The remaining pressure in the
system must be lowered, so-called depressurization (releasing pressure), before hose connections, plugs, etc. are opened in
the hydraulic system or brake system.
1.
2.
3.
Lower attatchment(s) to the ground.
Turn off the engine and remove the ignition key.
Release the system pressure by moving the control levers forward and rearward several times with full strokes.
All pressurised vessels must be opened very carefully, so that any residual pressure is released.
Check-tightening of leaking couplings and connections should only be done after all the pressure in the system has
been completely released.
All pressurized tanks/vessels shall be opened carefully so that any residual pressure is released.
Check-tightening of leaking couplings and connections may only performed after the system is completely
depressurized.
WARNING
Leaking high-pressure hydraulic hoses may cause severe injuries. Fine jets have high penetrating capacity on
bare skin.
To check for leaks, use a steel plate or stiff board, never use your hands.