My bike sat for a bit and when I went to ride it, the front brake had no pressure. Upon examination, there was no evidence of a leak of brake fluid. Bled the brakes and it was fine for a bit then due to weather the bike sat again for a while and again no brake pressure. No evidence of leaks again but somehow air is getting in the system. Anyone else experience this with their bike and can point me in the right direction as to possible problems to trouble shoot?

 

replace the rubber on the res? A busted diaphragm will cause issues. or the seals on the caliper. (last thing since there are no leaks). The diaphragm, the seal and making sure that all air is out of the system is my thinking. good luck edit: welcome to KF

 

Most likely air in the system. Also worth checking the master cylinder seal as this would allow fluid to pass back into the resevoir without actual loss.

Rob

 

this is the same issue i'm having, lever looses pressure after sitting for 3 or 4days after bleeding manually. no fluid/air back filling the reservoir, so i'm assuming my master cyl. ok? How can u make sure if there's an issue with the master cyl.? thanks..