Automatic pressure release

A hydraulic system 1 and a controller for a hydraulic system of a work machine are provided. The controller is configured to perform a work-tool disconnect routine to reduce pressure in a first work-tool line 20 and a second work-tool line 30 of the hydraulic system 1. The hydraulic system 1 comprises: a spool valve 10; a first work-tool port 22 connected to the spool valve 10 by the first work-tool line 20; a second work-tool port 32 connected to the spool valve 10 by the second work-tool line 30; a high pressure flow source of hydraulic fluid 40 connected to the spool valve 10 by a high pressure line 42 and a low pressure tank line 50 connected to the spool valve 10. When performing the work-tool disconnect routine the controller is configured to: check that a power source of the work machine is operating; instruct the high pressure flow source of hydraulic fluid 40 to provide no flow of hydraulic fluid in the high pressure line 42 to the spool valve 10; instruct the spool valve 10 to move to a first position wherein the first work-tool port 22 is connected to the low pressure tank line 50 and the second work-tool port 32 is connected to the high pressure flow source 40 in order to reduce a pressure in the first work-tool line 20; and instruct the spool valve 10 to move to a second position wherein the second work-tool port 32 is connected to the low pressure tank line 50 and the first work-tool port is connected to the high pressure flow source 40 in order to reduce a pressure in the second work-tool line 30.