How do you change hydraulic fluid on 424 international?

To change the hydraulic fluid on a 424 International tractor, first, ensure the tractor is on a level surface and the engine is off. Drain the old hydraulic fluid by removing the drain plug located on the hydraulic reservoir and allow it to fully empty. Replace the drain plug, then refill the reservoir with the appropriate new hydraulic fluid through the fill cap, checking the fluid level as you go. Finally, run the tractor briefly and check for leaks, ensuring the fluid level is correct before use.