27 - 2
Hose Burst Protection Valves
Pressure Testing - Loader Lift Ram
The following text describes the pilot valve setting
procedures and pressure testing sequences for ONE HBPV
only, repeat the procedures for BOTH loader arm lift rams.
Preparation
Before starting the pressure testing procedure vent hydraulic
system pressure as follows:
1 Park the machine on firm level ground, engage the
parking brake and set the transmission to neutral.
2 Lower the loader arms to the ground (not lifting the
machine).
3 Select 'ARMS LOWER' to raise the front wheels
approximately 25 - 50 mm (1 - 2 in) off the ground.
4 Switch off the engine.
5 Make sure all personnel are clear of the machine before
completing step 6.
6 Select 'ARMS RAISE' - this will vent residual hydraulic
pressure from the loader rams (head side).
7 Move all the backhoe control levers back and forth to
vent any other residual hydraulic pressure from the
backhoe service hoses.
Pilot Valve Setting Procedure
The pilot valve assembly, shown at C, must be set correctly
before doing the relief valve pressure test. If the pilot valve
is screwed too far into the HBPV it will create a flow path
connection from port C2 to port V2 (see descriptions of
operation).
To set the pilot valve assembly:
1 Remove pilot housing, item D, from the HBPV.
2 Check that the end face of the pilot valve assembly,
item C, is flush (level) with the end face of its housing
D, as shown at E.
3 If necessary, remove end cap F and, using a suitable
Allen key, adjust the pilot valve as required.
4 Refit the end cap.
Continured............
Section E
Hydraulics
9803/3280
Section E
27 - 2
Issue 1
Service Procedures
K
D
J
B
C
A
E
F
G
327330
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