i needed to get a front master cylinder for a 94 300 2x4 bought a used one from a 94 400 sportsman suppose to be same. i can not get it to bleed down for anything. wont bleed down by it's self. i used a master cylinder bleeder on it kit on it i have used on more than a few cars and trucks. still can't get it to bleed down. checked in side of reservoir the smaii bleed back hole is clear. the larger of the two holes i can see part of the cylinder piston ?????? think i got a bad used cylinder ? i don't have a banjo fitting on the brake line so i need to spin the cylinder on the brake line. it's the master cylinder that polaris only made for 2-3 years almost imposable to rebuild them polaris don't even have parts for it. or the special tool to do it. any ideas ?

 

Have you compaired your new one with the original one? It sounds like the piston in the new one is not returning all the way and is not allowing fluid to drop down in front of the piston. I'm thinking when you look down the front hole you should not be seeing the piston. Is there any adjustment on the push rod to allow the piston to return further?

 

nope if it has a broken coil on the spring . it's a throw away MS can't get parts and all most impossible to rebuild if you had the parts. about ready to sell it. nothing but trouble from day one. i gave up trying to put a new starter in it. damn rear clutch froze solid that a trip ?

 

Take it back off and try to bench bleed the master cylinder by itself in a vise, just using your finger over the outlet. Once you get it bled(if it will) put the cover on it, try not to leak any fluid as best you can and reinstall on the hose with the outlet port up(so fluid doesn't come out) and then install it on the handle bars. Then move the brake lever in small amounts(not all the way to the handle bar, just a 1/4 inch or so while watching for bubbles in the reservoir) Once the bubbles quit, start bleeding it like you normally would.

I've had them not bleed out easily with a new or rebuilt master cylinder until I did this. It may not work, but it's woth a try.

 

Before you quit trying, take the brake line off at the master cylinder, stick a tight fitting clear tubing piece into the master cylinder out line connector, return the other end into the holding tank of the master cylinder and add fluid in the tank. Start pumping until the brake fluid travels up the plastic line all the way back to the tank. Keep adding fluid so at no time you pump in air. Once the fluid fills up the plastic line right back to the tank and no more air bubbles are present, stop pumping, pull the plastic tubing out, re-attach the brake line and I am sure you will then be able to bleed the rest of the system.

Too often, air trapped in the master cylinder will not escape into the lines and you could spend days trying to bleed brakes whitout any success. The master cylinder needs to be bled by itself.

 

i was trying to bench bled it i have all the fitting to bench bleed it. i will try again saturday 90 % of the time they will start to bleed by them self after 10-15 min not my luck today. thanks for the tips