i think alot of it has to do w/ its a real small m.cyclinder and maybe lack of use makes it have problems. face it folks its not the best design but we get by w/ it most of the time. just my 2 pennies lol.

 

My 05 Sportsman started having rear brake problems with it was about 4 months old. I took it back to the dealer and they tried to bleed it, but it still did not work. They had to replace the rear master cylinder. Since then they work great, except my back brake sqeaks a lot when I ride now. I need to take the pads off and work on those to stop that. But I bet the master cylinder needs replaced.

 

I had to bleed mine, take the lid and rubber out of the resevoir, takes alot of pumping and bleeding but it will work eventually. Now i try to remember to step on it 2 or 3 times every ride,no more problems yet.

 

When i blew up my 03 TB 400 the rear brakes were working but i stripped everything off down to the bare frame and ive had it back together for about 4 or 5 months and ive bled the brakes several times and the rear brake wont work off of the foot brake or the hand brake.