Bleeding Brakes with Dual MC

[JP_REX]

Hi Folks,
I have a 67 coupe with the factory dual master cylinder. If I replace a hydraulic component on the front brakes, then only the front brakes have to be bled, is that right?

Thanks!

John

[cad-kid]

Sounds about right. When was the last time you bled the rear brakes? Standard brake fluid does absorb moisture. Perhaps you should flush the rear lines out when you are done with the fronts.

[notched]

You need to bleed the rears first. They always tell you to start with the wheel the furthest from the master cylinder.
The reason for this is because there are 2 pistons in the master cylinder. If you bleed the fronts first you will never be able get enough travel to properly bleed the second piston.
What you can do is put a small hose on each front bleeder and leave those bleeders open while you bleed the rears. Once the rears are bled, then do the fronts.
OR
get a pressure bleeder. :)

[BobWitt]

This is interesting... Most all dual-circuit brake systems i've worked with were split front/rear. So one 'circuit' was left front and right rear - the other circuit was right front and left rear... Corvair with upgraded system not this way? How were the factory-built dual systems split?

This is why I'm reading this whole forum - to learn...

Thanks...

[91blaze]

This is interesting... Most all dual-circuit brake systems i've worked with were split front/rear. So one 'circuit' was left front and right rear - the other circuit was right front and left rear... Corvair with upgraded system not this way? How were the factory-built dual systems split?

This is why I'm reading this whole forum - to learn...

Thanks...

Yes, the system is splint front/rear. I was able to bleed the front and rear brakes regardless of whether or not the other is bled. You only need to start with the furthest wheel when the entire brake system needs bled, so if you need to do only the fronts you can.

[Wagon Master]

Bobwitt, brakes split as you describe, I believe is a Honda thing and possibly other imports.