Honda FourTrax Rubicon TRX520FA5 2020 Owner's Manual page 190

Brakes
Rear Brake Fluid Level
RIGHT REAR
(1) UPPER level mark
With the ATV on a level surface, check the fluid level.
It should be between the UPPER (1) and LOWER (2) level mark. If the
level is at or below the LOWER level mark, check the brake pads for
wear (page 177).
Worn brake pads should be replaced. If the pads are not worn, have
your brake system inspected for leaks.
Other Inspections
• Make sure there are no fluid leaks.
• Check for deterioration or cracks in the hoses and fittings. If the
hoses are worn or cracked, have them replaced by your dealer.
180 Servicing Your Honda
(1)
(2)
(2) LOWER level mark