Tips for bleeding easily
I know this is a Rhino Forum, but I suddenly had the same issue with my Massimo UTV, so I found your thread before ordering a replacement Master Cylinder. I’m a retired auto tech and have used this process many times over the years with great success and, though this is an old thread and perhaps someone has already offered this solution, I thought I’d share with those who may have the experience today.
Using a 2’ section of small vacuum hose, a small Mason type jar with lid and some quality & fresh Dot 3 or 4 brake fluid, punch a hole in the lid of the jar just large enough to slip the vacuum hose into with a small 2nd hole for venting, if the hose hole is too tight to allow venting. Push the vacuum hose through the hole to the bottom of the jar and add enough fresh brake fluid into the jar to allow at least an inch of fluid depth above the end of the hose in the bottom of the jar. This will keep air from going back into the hose during the bleeding process! Keep the jar securely on the floor during the bleeding process to keep from making a mess on your floor.
Now, using an 8mm box wrench, if yours is the same size as my bleeder, move the bleeder cap out of the way to place the wrench over the bleeder and then slip the other end of the vacuum hose over the bleeder nipple to create a path into the jar, careful to make sure the hose is tight on the end to keep fluid from spraying everywhere when the brake pedal is pressed! I usually start with the rear brakes, which are accessible underneath, where the fronts may require you to remove the wheels to access the bleeders.
Now, with your Assistant ready to press & release the brake pedal (plus keep the fluid reservoir nearly filled), keep the bleeder closed while they press the pedal, open the bleed 1/4 turn and watch the air exit the hose in the jar. Make sure your Assistant doesn’t let up on the pedal until you’ve closed the bleeder! Keep in mind on the 1st one you bleed, you’ll be pushing the air out of the vacuum hose too, so the 1st one will take time to clear before you’re actually bleeding the cylinder and you’ll start seeing darker fluid coming out of the hose end in the jar. Keep repeating the process until you only see fluid coming out of the hose in the jar, moving on to the next wheel. As you continue, your Assistant should notice the pedal getting gradually harder to push, indicating air is being removed from the system. Whatever you do, don’t let the fluid reservoir get low because, if you do, you’ll have to start over and it will take even longer once air is pulled into the Master Cylinder!
Lastly, properly dispose of the old brake fluid and make sure any new fluid is well sealed, as it attracts moisture. I have photos of the process, but I’m not seeing a means to add pix to the Posts. Good luck, my brakes are again working perfectly!