You can inspect the fluid level of the rear brake using the sight glass at the rear of the master cylinder reservoir. a. Removing the cap at the top of the reservoir is crucial before carrying out significant scheduled maintenance. This makes it possible to see the fluid level, and it also makes it possible to condition it more clearly. b. After major maintenance, you should often clean, replace or drain the Harley braking fluid. It is nevertheless crucial to have a good understanding of the brake fluid condition at these services.  c. If the fluid is leaking or the cylinder is wearing out, having this understanding will help you spot the initial signs. Always remember that the foot brake pedal at the rear end is close to the reservoir of the rear cylinder. d. Detach the top cover and its seal. When detaching the top cover and its seal, proceed with extreme caution. DOT 4 Harley brake fluid may harm leather, painted surfaces, and plastic materials. However, there is no need to panic if DOT 4 brake fluid accidentally gets on a finished surface, but you should act quickly to wipe it up.  e. With a clean towel and a light glass cleaner, completely wipe it away. Before you open any parts that store or contain DOT 4 brake fluid, it's wise to get your cleaning tools ready and close at hand. f. Fasten the top cover with the aid of two Phillips head screws. You can reach these screws most easily with a Phillips screwdriver. This is because a Phillips screwdriver has a longer shank than usual.