A method of operating a hydraulic system of a loader arm carrying a working implement, the system having a ride improvement system and a selection valve connected to first and second chambers of a ram which operates the loader arm. A check valve assembly is provided, with the check valve assembly being responsive to pressure changes in the second chamber. The check valve assembly, when closed, prevents fluid from passing between the first chamber to the selection valve. Means are provided communicating the fluid pressure in the second chamber to the check valve, with the means responsive to pressure changes in the second chamber to open the check valve. The selection valve is operable to raise the loader arm with the system arranged to permit passage of fluid between the first chamber and the accumulator while permitting fluid to pass from the second chamber to a low pressure region.