The method of refueling the mountain bike oil brake is actually very simple: 1. Prepare oil first, and slow down the oil cylinder until it is flush with the ground; 2. Open the disc brake oil valve and drain the old oil first; 3. Take it out and slowly inject new oil into the oil injection valve with a syringe. Don't worry, so as not to see the oil on the cylinder; 4, and then exhaust, constantly have to brake, let the air out of the tubing, until exhausted.