My rear brake is pretty crap, anyone who has a ride gets a shock.

Its not that it doesnt work it just has a lot of travel in the pedal and well isnt very good.

What do you guys think? is this the norm on the trx?

It has fluid and no air in the line.

If there's lots of pedal travel, but for sure no air, it sounds like the master cylinder is at fault... try replacing it, it's an easy fix

before throwing the money on a master cylinder i would checl the travel of the linkage that pushes n the master cylinder. check to see that u dont have excessice play before it pushes the rod. if u do u should be able to just adjust it to take the play out, just dont tighten it up too much or the rear brake will drag

The bushing on the brake clevis is probably worn out where the pedal connects to the master cylinder. You can either buy a new OEM that will do the same thing in a couple months, or you can get the Fasstco brake clevis, and not have to worry about it anymore.