Dawson 4000M2, Operator'S Instructions/Spare Parts List

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4.2 Hydraulic Hoses - Layout and Connections
The EMV hydraulic fittings are metric for the EMV300. The pressure and return lines
(already connected to the vibrator) have metric 20 S. The pressure line is usually
connected to the bucket ram "extend" circuit and the return line to the bucket ram
“retract” circuit. The third, and smaller, drain line is fed either directly back into the
hydraulic tank on the excavator, or connected to the breaker circuit return line. The
fitting on the drain line connected to the vibrator is a metric 15 L male fitting.
Excavators will rarely have the same fittings as these on their bucket circuit so adaptor
fittings must be used.
Ensure all hydraulic connections are clean prior to fitting and that no contamination is
introduced into the hydraulic circuit during installation – this may cause internal
component damage to the hydraulic system or faulty operation of the vibrator or
excavator.
If quick release couplings are installed on the excavator they should be replaced. It is
strongly recommended that quick release couplings are not used for this application.
For permanent installation ball valves can be added to the excavator boom to ensure
rapid changing between bucket and EMV hydraulic function. As the bucket ram is no
longer in use, it should be retracted and fastened down.
WARNING: THE DRAIN LINE MUST FLOW DIRECTLY TO TANK
WITHOUT RESTRICTION. FAILURE TO DO SO WILL RESULT IN THE
HYDRAULIC DRIVE MOTOR BLOWING ITS CASING SEAL OR FRONT
CASING CASTING – THIS DAMAGE IS VERY COSTLY TO REPAIR.
The EMV is fitted with a motor case blow-off valve. This valve is effectively a check
valve that vents some oil to atmosphere should the motor case drain line pressure
exceed approximately 6 bar. It is not a pressure protection valve and is intended only
as an early warning valve, giving a visual signal that something is wrong. Any sign of
this and use of the EMV should be halted immediately and the cause investigated.
The blow-off valve does not guarantee the motor will be protected in all
circumstances!
Connect to
bucket ram
extend hose
Connect to
bucket ram
retract hose
Connect
drain line
directly to
excavator
tank!