Replacing brake lines

[Knight Rider]

Quick question:

I just replaced the rear brake lines on my 1999 Honda Civic DX and after all the hard work is done I need to bleed the brakes. I know how to do so, but my question is, Do I need to bleed the master cylinder because I completely removed the brake lines from the proportioning valve junction? does that allow air into the master cylinder?

 

[Trekk]

In theory, should only need to bleed it, if it ran dry.

 

[andrewthesith]

^ to add to that.. it won't hurt you to bleed them.

 

[Osiris19]

The master cylinder is bled whenever you bleed the air out of the lines through the calipers because you're constantly pouring fresh fluid in which forces the air down through the lines and out the calipers.

 

[Trekk]

The master cylinder is bled whenever you bleed the air out of the lines through the calipers because you're constantly pouring fresh fluid in which forces the air down through the lines and out the calipers.

That is not correct.
Air only enters when no fluid is present. Since brake fluid is heavier then air, it will displace the air from the reservoir during bleeding.