I have a 85 244ti and installed a new master brake cylinder.I bled the MBC before installing and used the Power Bleeder to take out any air from the system.The peddle is a little soft,I thought I removed all the air in the system.So when using the Power Bleeder is it possible that air is left in the MBS because you don't move the piston like if you where bleeding the system the old way?Now I'm 2nd guessing the method of power bleeding.Is it a concern and should I bleed the brakes the old way? Thanks,Charlie

Its a miracle if you can swap an MBC and not wind up with air in the system. You need to bleed the entire system, period. Besides, swapping out all the old contaminated fluid with fresh is a great thing!

jorrell
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92 245 278K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

I've never bled the system after swapping a master cylinder. I bench bleed the new cylinder, connect up the pipes a turn loose, then very cautiously press the pedal to expel air at the leaking joints but without pumping any down the pipes.

Expelling old fluid and dirt is another matter. That's worth doing say every 3 years anyway, without dismantling anything, just power-bleeding each nipple in turn until the fluid runs clear.