I'm almost ready tp throw the whole system in the trash, lol. I have a 2016 Evo 300 4T, the rear brakes have always squealed and kinda sucked. I've read all the horror stories about bleeding them so I never really had any desire to deal with it, I did get some of the copper brake goo on the back of the pads and that kinda helped the super annoying squeak, they will lock up the rear wheel so good enough. Fast forward to a week ago I finally got rear pads, opened the top of the master cylinder and tried to gently pry the pucks apart in the caliper, one is seized, the other just oozed out some fluid. Nice, time for a rebuild kit. I took it all apart (act of desperation?), cleaned it real nice, soaked the orings in soapy warm water for a bit, put it all back together but it was done. I resigned myself to not riding on this beautiful weekend, so I instead rebuilt the front forks (leaky seals beyond cleaning with film), did the clutch fix and built 2 new sections in my course, not bad I guess.
Rear caliper rebuild kit arrived on Monday, time to do the deed. I reinstalled the old pads as this was going to be messy for sure. Cleaned up the master cylinder (didn't open it up) and started the process. Pucks in, went in smooth, added some fluid into the caliper to get air out and started the process of bleeding them. I have the caliper mounted up at about muffler height (clamped to a chair) and some wood in-between the pads. I'm starting nice and easy, bleed the top banjo bolt on the cylinder and I'm not really getting anywhere. Bleeding out of the nipple and not getting anywhere, the hose is 3ft long up and over the rear fender. Air bubbles keep coming out, where is this coming from?! Banjo bolts again, more nipple work. Still nothing and I'm on hour 2 at least. I take the caliper apart again, just to check, the pucks are moving good. Next day, back at it, using a philips screw driver to pump the cylinder, and I kinda get some feeling but a test ride reveals nothing. I try the reverse bleed now (hour 2 of this day?) and it helps a bit, some more banjo bolt bleeding and cursing and I have some ok feeling. Went for a 1hr ride and while the rear brakes work, they will not lock up the wheel and the squeal is so damn loud that everyone within a mile knows what's going on (probably because those old pads got soaked in brake fluid in this fun process). I park it as its dark. This morning no brakes, pedal to the floor. Try bleeding them off the bike, nada. I install the new pads and get some decent feeling but a test ride lets me know that the decent feeling is ****. I've now drank a bottle of wine and feeling good, otherwise I'm not happy with the brakes, this has been going on for days when I should be riding.
So what's my options, a rebuild kit for the master cylinder? I've bleed the clutch and front brake on this bike but the rear brake is like nothing I've done before. I hate it hahahaha. Thanks for reading my rant and look forward to suggestions or more drinking