2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 421Get this manual
HYDRAULIC BRAKE Coat new O-ring with DOT brake fluid and install it onto the reservoir hose joint
Apply locking agent to the joint screw threadsInstall the reservoir hose joint into the master cylinder and tighten the screwTORQUE: (0.2 kgfm, 1.4 Ibfft)
Connect the master cylinder push rod to the brake pedal with the joint pin and new cotter pin