The John Deere utilises a closed centre hydraulic principle and because of this it is necessary to modify either the tractors’ external oil supply or the hedger main control valve.

There are two alternatives.

1. A flow limiting valve, manufactured by John Deere is available to provide an ‘open centre’ external supply. For further advise consult your John Deere dealer.

2. A control valve conversion kit-Part no. 81 30 059 consisting of relief valve blanking plug, which should be installed in place of the existing relief valve, and a pressure gallery blanking plug, which is installed in place of the standard blanking plug, at the outlet next to the lift ram gland connection.

Take care when extracting the relief valve not to damage the copper sealing washer as it is re-used.