How to bleed a new clutch master cylinder?

Question

My CMC was shot, here is what i have done:

1) Replaced CMC,cleaned reservoir.
2) Attached clear tube to bleeder and filled reservoir with new fluid, opened bleeder and pumped clutch till all old fluid came out and i saw new fluid exiting bleeder into clear tube. So it is now flushed.
3) I want to now pressurize and bleed the system. I have 2 people for the job.

a) attach new piece of clear tube on bleeder.
b) have jar, half filled with fresh fluid that clear tube is submerged in.
c) the reservoir is now filled to the max .
d) my plan is to open bleeder, have other person pump clutch to get all air out of line. when bubbles stop i know air is out.
e) when bubbles stop, i will have person hold clutch down, close the bleeder then release clutch.

I was told not to let fluid in reservoir get below MIN line or new air in introduced. Do i need to keep reservoir cap on during bleeding? What if I need to add fluid? Does air only get sucked into reservoir if clutch is pumped?

Please add or change anything that you think i should do differently. Thank you so much. :) have a good day

Answer 1

i own a repair shop and if you dry pump this ,you,ll burn the cylinder back out ,what you have to do is open a bleeder and gravity bleed it out,it takes longer but its the best method of doing it ,some on here will tell you to pump bleed it,if you do it will damage it,i have done this for 36 yrs,and believe me i have did my fair share of these,gravity bleed it until all good fluid comes out of it keep it full at all times,and then close off the bleeder,and slowly push down on it a few times this should complete the process,good luck with it hope this helps.

Answer 2

You don't need to have the cap on as long as the fluid level does not go below the mininum marking while you are bleeding...sometimes when bleeding the fluid will squirt up out of the master and get on your paint, so you may want to place the cover on it anyway...just so you can top off the master as you are bleeding. The only thing wrong with your procedure is the assistant should not pump the pedal...you want them to hold steady pressure while you crack open the bleeder and then close the bleeder before the pedal bottoms out and repeat.
Another method that's used on semi's is to fill the master with fluid, crack the bleeder and allow it to drain slowly into the glass jar as you've described and just keep topping off the master....that might take a little longer but it will eventually purge any air out of the system.
Good luck, Paul