SHB 803 en – Edition 2.4 * 803s312.fm 3-33
Maintenance
Adjusting primary pressure limiting valve 1 (PPLV 1)
☞Adjust the pressure at the primary pressure limiting valve (PPLV 1) A on the main valve
block
☞Loosen the locknut of the pressure limiting valve
☞Unscrew the pressure limiting valve until you can read off a pressure drop on the
pressure gage
➥The valve seat may be stuck and must be loosened first
☞Adjust the pressure limiting valve and tighten the locknut
☞Check the primary pressure limiting valve 1 and the pressure drop once adjustment is
over
Also check by extending/retracting the stick cylinder!
Pressure check of gear pump P1
Hydraulic supply for swivel, bucket and boom functions
Checking primary pressure limiting valve 2 (PPLV 2)
☞Install a pressure gage with a T-fitting (EVL 8L no.1000015515) and a measurement
connection (8L no.1000015578) temporarily on the boom cylinder.
☞At maximum engine speed, actuate the boom cylinder as far as it will go to
either side
Checking pressure drop
☞At maximum engine speed, actuate the boom cylinder as far as it will go to either side
☞Swiftly reduce engine speed from maximum to minimum -> pressure drop
☞Check and make a note of the pressure value.
➥Pressure drop should not exceed the specified value by more than 10 %
Adjusting primary pressure limiting valve 2 (PPLV 2)
☞Adjust the pressure at the primary pressure limiting valve (PPLV 2) B on the main valve
block
☞Loosen the locknut of the pressure limiting valve
☞Unscrew the pressure limiting valve until you can read off a pressure drop on the
pressure gage
➥The valve seat may be stuck and must be loosened first
☞Adjust the pressure limiting valve and tighten the locknut
☞Check the primary pressure limiting valve 2 and the pressure drop once adjustment is
over
Also check by extending/retracting the boom cylinder!
Fig. 31: Primary pressure limiting valve 1
A
Fig. 32: Primary pressure limiting valve 2
B
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