I have 13 500ho, and in doing my spring maintenance I noticed the foot pedal goes down to the foot well with zero resistance. I never use it so figured maybe it was full of air. I tried and could not get it to bleed, only a drop or 2 came out the bleeder screw with every pump. The fluid level never dropped from the tiny reservoir either, and was full when I started. Do the master cylinders often fail, or is there a different procedure to bleed properly? Also can I run without it for a bit, or is it a shared piston with the hand brake and I could lose the rear brakes there too?

 

A mityvac works better if you have one. Normal for these small master cylinder seals to crack and also suck air especially if not used often. Seal kits are available along with complete master cylinders if needed.Polaris Sportsman 400 500 600 700 800 Rear Foot Brake Master Cylinder Seal Kit | eBay http://www.ebay.com/itm/New-Rear-Brake-Master-Cylinder-For-Polaris-Sportsman-335-400-450-500-600-700-800-/221822583476?fits=Make%3APolarisLooks like the m/c has been updated,but the seal kit should work. If a new m/c is needed you can get one here. http://www.cyclepartswarehouse.com/f...13&fveh=284378

 

Ok, thanks. Any idea if the 2 systems (hand brake and foot pedal) are isolated from eachother? I assume as there is 2 dif bleed screws. Glad to see there is seal kits

 

Yes the rear caliper is split,has one chamber for the rear brake master cylinder and one chamber tied into the main line that feeds the front calipers,the reason for the two bleed screws. Your front brake can still put pressure on the rear caliper,but most of the stopping force is on the front brakes where it should be. Something like 60/40. The rear brake was actually designed as an assist to put more pressure on the rear caliper as well as an emergency brake in case the front brakes lost pressure. The only time when this system gets screws up is when you don't use it as you've found out,plus if the small o-ring that separates the caliper chamber leaks. When this happens it can push fluid back toward the foot pedal and small master cylinder and reservoir and you can feel pressure in the brake pedal when you pull the brake lever. You can live with out the rear brake,but it's best to get it working and use it every now and then just to keep the seals pliable. Whether it takes installing a seal kit or just getting a new master cylinder if you can't get the old one to bleed properly and have a decent rear brake.