and left. The control levers must be shifted to all
directions to relieve trapped pressure.
To prevent damage on the components and
structure, a machine fitted with thumb must also
be equipped with a pressure relief valve on the
accessory circuit. Check with your Volvo Dealer
that your machine is properly equipped.
The thumb is only approved for use with Volvo
designed or approved buckets and attachments.
If the thumb is used with other buckets or
attachments, it may not work properly.
If the thumb is not used for some time, disconnect
the hydraulic lines to prevent thumb cylinder drift.
Connecting and disconnecting thumb
1 If the hammer / shear valve in the front of the
cooling package is not in the correct position,
turn it 90° clockwise to vertical position (A).
V1142525
B
A
Hammer / shear valve
V1142527
B
C
A
Left side of the dipper arm
Operating techniques
Thumb
115