3-34 SHB 28Z3 EN – Edition 2.0 * 28z3s312.fm
Maintenance
Pressure check of variable displacement pump P2
Hydraulic supply of stick, left-hand side drive and auxiliary hydraulics functions
Checking primary pressure limiting valve 2 (PPLV 2)
☞ Connect a pressure gauge to measuring port MP 2 42/2
☞ Extend the stick ram as far as it will go at maximum engine speed
☞ Check and make a note of the pressure value.
Checking pressure drop
☞ Extend the stick ram as far as it will go at maximum engine speed
☞ Swiftly reduce engine speed from maximum to minimum -> pressure drop
☞ Check and make a note of the pressure value.
➥ Pressure drop should not be more than 10 % of the specified value
Setting primary pressure limiting valve 2 (PPLV 2)
☞ Adjust the pressure at the primary pressure limiting valve (PPLV 2) 43/B on the main
valve block
☞ Slacken the locknut of the pressure limiting valve
☞ Unscrew the pressure limiting valve until you can read off a pressure drop on the
pressure gauge
➥ The valve seat may be stuck and must be slackened 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 with the retract stick and the left-hand side forwards/reverse drive func-
tions!
Checking the auxiliary hydraulics pressure
Notice!
Factory indications for auxiliary hydraulics secondary valves are possibly invalid –
adapt these values to the attachment!
2
Fig. 42: Measuring port P2
Fig. 43: Primary pressure limiting valve 2
B
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