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Section E
27 - 1
Hose Burst Protection Valves
The hose burst protection valves (if fitted) prevent the loader
or backhoe falling in the event of a hose burst. These valves
may be fitted on rams which raise or lower the loader arms,
the boom or the dipper.
Checking
1
Raise the loader arms fully. Raise the boom to about
45° . Raise the dipper to the horizontal.
2
Stop the engine
Using the control levers, try to lower the loader, boom
3
and dipper. Push the levers fully to the 'lower' position.
If there is any movement, adjust or replace the hose
burst protection valve as applicable.
S320930
A
C
B
A171340
9803/3280
Hydraulics
Service Procedures
D
S170582
Purchased from www.WorkshopManuals.co.uk
Lowering a Load - In a Failure Condition
During normal operation, the engine must be running before
a load can be lowered. The following paragraphs describe
how to safely and correctly lower a load in the event of
engine failure or a hose burst; we recommend that only a
competent maintenance engineer perform the procedures.
After lowering a load do not use the machine until the
manual over-ride screw has been reset (Loader HBPV, refer
to Pressure Testing - Loader Lift Ram) or a new end cap
and valve assembly fitted (Boom HBPV, refer to Hose Burst
Protection Valves - Dismantling and Assembly), otherwise
the valve will not operate as intended.
!
DANGER
Do not stand underneath the raised load during the
lowering procedure. Stand clear and to one side until the
load has been safely lowered. Make sure that the area is
clear of other people before lowering the load. If you do
not follow these precautions you or others could be
killed or seriously injured.
2-3-5-3
Boom and Dipper Hose Burst Protection Valve (HBPV)
Remove cap A and pierce the warning label.
1
2
If a hose has burst, position a suitable container to
catch the oil.
3
Insert an 6mm allen key into the socket head of screw
B. Slowly turn the allen key in a clockwise direction until
the load just begins move.
Burst hose - Lower the boom using screw B, turn the
screw counter-clockwise to slow or stop the load from
lowering.
Dead engine - Operate the control lever in the cab to
lower the load.
Loader Hose Burst Protection Valve (HBPV)
1
Remove cap C from both HCPV check valves on the
loader lift arms.
2
If a hose has burst, position a suitable container to
catch the oil.
3
On the burst hose HBPV, insert an 5mm allen key into
the socket head of screw D. Turn the allen key in a
clockwise direction so that the screw winds fully in.
Repeat slowly for the opposite side as the load is now
supported on this HBPV.
Note: Count the number of full turns on each screw for
resetting purposes.
4
Operate the control lever in the cab to lower the load.
Section E
27 - 1
Issue 1
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