A few days ago a put question about no pressure at all at the lever whilst trying to bleed the brakes of a 1999 r6.Nipped in to my local yam dealer he said the prob cause is using 3 year old dot 5.1,because once opened its only good for a few months.Tried some new dot 4 same so went to fasttrack in Leicester asked the mechanic he said its a air lock in the master cylinder.Crack open the bango bolt at the m/cylinder and us it as a nipple on your caliper SORTED
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the difference between talking to a sales man or the guy who knows, a mechanic
Thing is. Air will rise, even through brake fluid. It will find the high spots in the system. With clip on style bars sometimes the banjo bolt is higher than the escape route for air into the reservoir.
As well as cracking the banjo to let air out undoing the clamp and hanging the master cylinder at the appropriate angle should also encourage air into the reservoir. Even turning the handlebar to left lock can straighten the angle enough to put the banjo lower than the reservoir escape hole.
Any air collected under the bellows should be expelled to eliminate possible absorption of water into the fluid.
That's my take on things anyhow.