Bleed Master Cylinder Or Not When Flushing System?

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I changed a brake hose and caliper on my Expedition and accidentally emptied master cylinder during repair. I plan to flush the old fluid from all 4 of my brake lines, so my question is whether I need to remove the lines from the master cylinder first to bleed the master cylinder, or if it will bleed itself while I am pushing the old fluid from the lines. I plan to gravity bleed the front brake line and caliper that I replaced first (After re-filling the master cylinder).
 
The master will be bled when you bleed the lines, buy why push that air all the way through?
I would bench bleed it, unless you have a power bleeder which makes things easy.
FYI, using a Motive Bleeder was the only way I was able to get a pedal in C3 Corvettes.
 
The line and caliper I replaced was passenger front. I saw one video where the person used a clear hose from the front caliper back into the master cylinder reservoir and pumped brakes until all air was pushed out. Makes sense to me in theory. Any reason this would not work?
Then I could bleed the rest of the lines.
 
Originally Posted by Fitz98
The line and caliper I replaced was passenger front. I saw one video where the person used a clear hose from the front caliper back into the master cylinder reservoir and pumped brakes until all air was pushed out. Makes sense to me in theory. Any reason this would not work?
Then I could bleed the rest of the lines.


In some cars, the master cylinder is angled upward. So some air can get trapped in the tip of the master cylinder. You'd have to remove the master cylinder to bleed it properly.
 
After you've had all the fluid run out of the reservoir, you're almost certainly going to need to bleed all 4 wheels anyway, best to just do that from the start.

It isn't necessary to bench bleed master cylinder except when installing a new one that has absolutely no fluid inside.

Best to never reuse brake fluid that comes out. Brake fluid is cheap compared to parts damaged by contaminated fluid.
 
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Thanks,
I bled master cylinder on truck into a bottle to get rid of air and old fluid. Will bleed air from replaced front calipers and lines first, then go to rear wheels and then come back to front passenger side and finish drivers front. That should get all old fluid out and air. Master cylinder is on firewall drivers side.
 
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