Brake Bleeding -Why does pedal get soft after time?

[Ironangel]

Heres one that that has blown many minds. The bleeders have terrible wheel cylinder and caliper thread fitting issues. Many are machined in China, the USA and or both. Understanding that air compresses and fluids do not, sometimes air can be sucked in right past those threads on the bleeders when they're open. You can sometimes see this using Mighty Vacs with clear vinyl tubing with the presents of endless tiny micro bubbles while pumping the Vacuum lever. Smear only the threads with a small amount of this stuff https://shop.advanceautoparts.com/p/...E&gclsrc=aw.ds
and "gravity bleed" each rear wheel cylinder independently...If the problem persists, do the front bleeders. If the problem persists, then air is either getting in past the cups, or caliper piston seals, or is trapped in the system at the MC and/or the PV. Tiny bubbles will gather to be come big bubbles over time...