Front brake not braking

[91cb-1]

I just bought a new cb1 red this time i transferred the tank shock and front brake master cylinder, now the shock's workin great and the tank needs re sprayin (as it's Black) but no matter what i do the front brake won't work, i've bled the thing till the fluid is crystal clear and when that didn't work i pumped the fluid up from the caliper, still no dice, any tech heads out there with a solution or a diagnosis of what's wrong? Help much needed, thanks.

[sparkybloke]

i take it you can pull the lever back to the 'bar? this would mean you either have air in the system(most likely) or hydraulic fluid is leaking out ( usually very noticable). when you were bleeding through did you ensure the reservoir was topped up all the time? some times you can get air trapped in odd places and need to be quite patient and steady bleeding through, or leave it overnight with a cable tie pulling the lever in sometimes does the trick. was the master cylinder seen in working order b4 you fitted it,the rubber parts could be tits if left to dry out over time.do both pistons on the caliper move back in if compressed?

[91cb-1]

Ya lever moves right back to bar, i've left it for two nights and i pumped fluid up from the caliper itself, i don't think it's trapped air, i transferred the master cylinder from my old bike, and it was working fine i haven't looked at the caliper yet i was hoping to leave that to the last resort, i've got a spare front caliper but i wanna change pistons and seals on it before putting it on, and i gotta wait to get money before i can do that, i'll have a look at it morrow and see what i can do about it, i just left the bike as it was with lever extended, i'll try a cable tie on it tonight but i don't think thats what it is. thanks all the same for the help!

[sparkybloke]

if you arent getting any fluid leaking then its gotta be trapped air bubble/s unless the master cylinder is knackered and fluid is passing thro it instead of forcing calipers closed

[91cb-1]

Bollox that's what i had in my head too, i don't fancy changing the master cylinder only cause it's a messy bastard and my ma will kill me! i'll give it a shot morrow, i've got a cable tie on it now for the night and hope that fixes it! fingers crossed, thanks a lot for all the help though man.

[91cb-1]

Was just draning the the line to change the master cylinder and hey presto it decides to work, fuckin right on, so i bled the line again just to get all the air out and it's workin great.

[sparkybloke]

allways leave overnight if a job is pissing me off, seems a lot clearer next day