The technique shown in this tutorial for bleeding Shimano brakes works surprisingly well. It avoids using a syringe, it is as clean as it possibly can be with the oil involved, it is quick, and it is effective for getting air out of the brake system! While the video shows how to bleed mountain bike brakes, it works as well for road bike brakes – I used it to bleed a Shimano GRX groupset. Recommendation.