I have tried to completely change old brake oil with new one on a cable-pull or cable-actuated hydraulic brake caliper. You have likely seen the same calipers with different brand names. This type of calipers are recommended only as upgrade from V-brakes and should not be considered as cheap alternative to a proper hydraulic brake system with dedicated calipers and levers.

If you know an easier way to completely flush old brake oil on this type of calipers, then let me know in the comment section of this video. Thanks.