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Section 3
27 - 1
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 Hose Burst Protection Valve
1
Raise the loader arms fully. Raise the boom to about
45° . Raise the dipper to the horizontal.
2
Stop the engine.
3
Using the control levers, try to lower the loader, boom
and dipper. Push the levers fully to the 'lower' position.
If there is any movement, get the hydraulic system
checked by your JCB distributor.
S320930
A
B
9803/3280
Routine Maintenance
Hose Burst Protection Valve (if fitted)
C
D
S170582
A171340
Purchased from www.WorkshopManuals.co.uk
Lowering a Load
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) or a
new end cap and valve assembly fitted (Boom HBPV) by a
qualified engineer, 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)
1
Remove cap A and pierce the warning label.
2
If a hose has burst, position a suitable container to
catch the oil.
3
Insert a 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 HBPV 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 a 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 3
27 - 1
Issue 1
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