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Reply to "Brake Fluid - will it absorb air?"

Here is a link that explains how to monitor new brake fluid for excessive air by measuring oxygen content.
It mentions new brake fluid is dehydrated, thus readily absorbs air. When new brake fluid is injected into new vehicles bubbles are inevitable. The dry fluid absorbs these bubbles, so it is not necessary to bleed the system afterwards on the assembly line.
Perhaps this has something to do with why the overnight tie-down method works. The applied pressure which can be as much as 500-psi or more helps the fluid absorb air into solution. As the pressure is released or decreases over night from leaked-down the now hydrated fluid retains some of the air. The dry brake fluid acts like a sponge until saturated.
• This link says the system for testing brake fluid must have an upper limit of 1000-psi for testing.

Maybe as the brake fluid ages its saturation is greatly reduced, thus reducing the effectiveness of this method.
I still don’t know and will continue searching for the answer.

Solutionized is usually used when discussing molten metal.
Last edited by scottmitchell