ok so does anyone know exactly what goes wrong with the rear brake.. does the caliper itself goto hell or is it somthing else...

 

All of my rear foot breaks on my machines have not worked from day one or shortly after. Not sure what the problem is and would like to know. Seems like the plunger on one of my leaks break fluid, could be a seal. The other one just pushes to the floor board and does nothing, has lots of break fluid in the reservoir though. seems like a saftey hazard to me.

 

I went through a similar problem about a month ago.
My rear brake pedal on a 500 HO never really worked well.
Recently I had the rear caliper lock up. It ended up needing a piston seal kit which I installed myself.
In bleeding the system I realized that there is a bad seal on the rear break plunger (cylinder)and unless I change the rear brake cylinder the foot pedal won't ever work. I only use it now to get it into park and hi range.
They don't make a rear cylinder rebuild kit , you need to replace the entire unit. For what Polaris gets for it it's out of the question. Used would be just as bad.
I'm thinking my rear caliper went bad because of something to do with the rear cylinder going dry and letting moisture into the rear caliper. The rear caliper is a two stage deal,the hand brake and the foot brake operate one common piston on the rear caliper.
I'm not going to fix my rear brake cylinder but I am going to make sure the resivoir under the seat has fluid in it.
Not sure if this answered anything, but I recently worked on a similar problem.
Deerkiller

 

HAD SAME PROBLEM ON MY 06 500---WHAT I DID WAS SIMPLE---I FILLED A 5 GALLON BUCKET WITH ROCKS-PLACED ON MY REAR PEDAL AND LET STAND OVERNITE---THIS GOT AIR OUT OF SYSTEM AND HAVE HAD NO PROBLEM SINCE--I GOT THIS FROM A PREVIOUS THREAD ON THIS FORUM

 

the problem is because polaris changed to a hydrolic system.96 and before used manual rear brakes that can be adj.tight and worked 100% better which still was not like the front master cyl.which has four times more fluid in the res.able to be compressed. its a design flaw.on its best day it aint much.its actually designed as a emergency brake.with my fronts if i hit it hard it will stop 40% quicker only if i damn near stand on the petal.what i'm going to do is either put another handle+master on the right side handelbar or rig it to work with the pedal which would be the best way.i have a fully functional shop to make brackets to adapt the foot brake to the bigger mastercylinder.it would stop 300% better guarenteed!!!!