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Discussion Starter #1
Im sure this has been covered 100 times but I cant find it - Anyone have any magic ways to get the rear brake bled - Full of fluid but rear master cylinder will not build any pressure - I seem to find this same problem on most older Polaris models
 

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Uh, you posted this in the "Scrambler" section. Probably makes no real difference though as the brake is about the same. Take the line loose and see if you get anything. If not, you need a new MC. They fail pretty often on older machines.
 

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Discussion Starter #3
Do you have a preference on OEM vs aftermarket ? And sorry it is a scrambler - My sportsman also has the same problem and I replaced the rear MC with an aftermarket part and never got it to build pressure to blled it
 

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Aftermarket. I’m not sure it is a MC issue. When i took the old one off, it still seemed to have plenty of pressure when you put your finger over the outlet port with the hose off.. I just may have an issue with the caliper itself.
 

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Discussion Starter #7
On my sportsman I replaced the rear MC and the rear caliper and never could build any pressure to bleed - I have heard a few tricks like leaving the brake pedal weighted open overnight but still got nothing !
 

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Bleed the MC first - remove the line, depress the pedal, hold your finger over the line port and release the pedal - usually within 5 pumps, the MC will build enough pressure that you cannot prevent fluid from coming out of the port with finger pressure - at this point, push and hold the pedal - attach the line securely before letting off the MC - remove the caliper and brake pads - holding the caliper so the line fitting is at it's apex, use a c-clamp to push the piston fully into the caliper - brake fluid and air will be expelled into the MC reservoir, leave the c-clamp in place - if the fluid is discolored, sop it out with shop rags or paper towels - fill the reservoir with clean fluid from an unopened (or recently opened) container - pump the brakes to assess the pressure applied to the caliper - if adequate pressure is being applied, the rubber line and c-clamp will flex and relax each time the MC is pumped - if necessary, push and hold the brake pedal, while holding pressure on the system, crack the line fitting at the MC to release any trapped air - if necessary release, re-push and hold the brake pedal again - crack open the bleed screw to release any trapped air - the brakes are now bled - fill the MC reservoir to the upper mark and cap the reservoir - remove the c-clamp from the caliper - to assure all air has been expelled, pump the caliper piston out about 1/2 to 3/4 inch - again holding the caliper with the line fitting at the apex, push the piston back in - install the pads, install the caliper, pump the brakes until the brake pads contact the rotor and you have acceptable pressure on the system. NOTE: do not top off the fluid reservoir - the fluid level becomes an indicator of pad wear - when the pads need replacement, the level in the reservoir will be very low - pressing the caliper piston in to install new pads will restore the fluid level - if the reservoir is topped off between brake pad changes, the reservoir will be overfull when the piston is depressed into the caliper and excess fluid will have to be removed to allow the piston to be fully depressed.
 

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Discussion Starter #9
Thank you late bird going to give that a try on both of my Quads . I remember bench bleeding car master cylinders that way years ago !
 
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