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Brake bleeding

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Cool53:
If you are pressure bleeding or pedal bleeding you need to keep the pressure at 25# or less. Any more than that and you are turning the brake fluid into soda pop. The big bubbles break down into millions of small bubbles when you push hard when pedal bleeding, infusing those bubbles into the fluid. When you get done you may have a pretty good pedal but after letting the car sit for several hours you get back in and the first application goes low, maybe to the floor. While it was sitting all the little bubbles got together and became one big bubble. Pressing on the pedal "carbonates" the fluid once again. Gravity bleeding is best, but some system don't lend themselves to it, especially those with low mounted masters and those with fluid check valves.
Brake fluid is cheap and should be changed annually. It is hygroscopic and absorbs moisture. Fluid that boils at 375 dry will boil at under 300 or less once it absorbs enough water. That's why road course cars and stock cars change fluid all the time. And your parts won't oxidize.

EDNY:
Jef

Was taught to bleed from the furthest wheel first, watching the All Girls Garage ;) the other day..they began with the closest wheel first.  Never had a problem with my sequence ???

I prefer gravity bleeding - normally because no one is around to help.  If I can't get gravity method to flow, I just open the bleeder fitting and give the pedal a slight push down to get the fluid started.

Ed

Cool53:
All correct, them girls don't know nothin'.

Cool53:
Just kidding girls!!!!

ghost28:
 Good to know about the tiny bubbles I have never had a problem with them that I know of, but I will watch my pressure when bleeding brakes from now on. On the last two cars I built I had to put heavy springs on the pedal swing arm on an under floor master cylinder because the pressure from the weight of the pedal made the break fluid heat up then swell causing my brakes to lock up. I know sitting to close to a heat source like exhaust will cause the same thing to happen. Opinions?

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