R1100R Rear Brake Bleeding

Folks, I looked through the relevant and related topics but I'm still stuck with bleeding the rear brake on my R1100R. Did both front sides using the MityVac and all went well. For some reason no matter how much vacuum I pump - ~25PSI, nothing comes out of the bleed nipple. I removed the cap from the reservoir and kept unscrewing the bleed nipple almost to the point I was worried it my just come out, and no brake fluid is flowing out. I've avoided using the rear brake lever so far and leaving that as the last option. Am I missing a step or the nipple is plugged and need to be replaced? I did replace as much fluid I could from the reservoir for now until I get the job done.

Thanks in advance.

Folks, I looked through the relevant and related topics but I'm still stuck with bleeding the rear brake on my R1100R. Did both front sides using the MityVac and all went well. For some reason no matter how much vacuum I pump - ~25PSI, nothing comes out of the bleed nipple. I removed the cap from the reservoir and kept unscrewing the bleed nipple almost to the point I was worried it my just come out, and no brake fluid is flowing out. I've avoided using the rear brake lever so far and leaving that as the last option. Am I missing a step or the nipple is plugged and need to be replaced? I did replace as much fluid I could from the reservoir for now until I get the job done.

Thanks in advance.

Afternoon kalali

Did you remove the little bladder from the rear reservoir? Easy to miss that & just have fluid on top of the bladder not down in the reservoir.

Personally I don't like to use vacuum bleeding on the ABS-2 systems as that doesn't move much fluid with much force.

If you just can't get any fluid out even with pumping the pedal then check the pedal adjustment to make sure that the master cylinder piston is FULLY returning. If the piston isn't fully returning then it won't open the little take-up port to allow any new fluid into the cylinder bore.

Hi dirtrider, thank you for the quick response. The bladder and the lid came off as one piece so no issue there. I haven't tried pumping the pedal yet and don't know how far should the rear brake pedal travel under normal conditions but mine is fairly short - about 3/4", so maybe it needs to be adjusted to allow for the fluid to move freely into the bore. I'll try give them both a try and see if I can get the fluid flow from the nipple.

Thanks again.