rear hydro brake

Haven't even seen a hydro caliper. But they should be very similiar to automotive ones. Just take it apart, clean it, replace the rubber parts, lube it up with rubber grease and put it back together. Cannot use regular grease because it will cause the seals to swell and fail. Should not be that difficult. Refer to the service manual.
 
you dont need a back brake!! lol ive got a hydro brake on back of mine but it doesnt work :D
 
Take the caliper off.There are slides on most all yamahas with rubber around them.Take them out,take the pads out,the rest is self explanatory.Just clean it with a wire brush,wire wheel,etc. Put new caliper grease on it and just clean up the slides and lube them well.Auto stores sell the grease in small packets for $1 a pack.Hope this helps