Just purchased new left handlebar lever w/ mastercylinder it has some clear fluid in it but do i have to put bike fluid in it when i press the handle it doesn't apply the rear brake

 

did you use DOT IV? did you bleed the brake? can you see if the piston on the handlebar is operating/stroking?

 

the piston is stroking but how do i bleed and i havent added anything so im thinking theres no fluid in it for them not to work its brand new

 

how do i put it in and how much?

 

does it look like this?
if so, take them 2 screws out, remove the lid, fill it to where it's full. then go to your caliper on the rear, there's a bleeder nut. just like on your car/pick up, bleed the brakes by pumping the brake handle and keeping fluid in the reservoir. you gotta get the air out so the hydraulic system will work. savvy?

 

si saber thanks got it

 

how often should i grease the rear end and the brakes i see grease fittings and the bikes been sitting up a while