Do vacuum brake bleeders work? If not, what kind do you recommend?
06-16-2007, 09:20 AM
#4
Pressure bleeders work - but the results are not as good
They're great for single-handed flushing the system. But there's a noticeably worse difference in pedal feel. Stoptech had a tech article warning that pressure bleeding forces air/moisture into the brake fluid altering it's ability as a hydraulic fluid.
Best way to do is still 2 guys with one pushing the brake pedal.
Best way to do is still 2 guys with one pushing the brake pedal.
06-16-2007, 10:05 AM
#5
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???
That doesn't make much sense.
The difference between atmospheric pressure and that plus 10psi, especially with the water content of the air, just isn't enough to think about, when talking about how hydroscopic brake fluid is.
I doubt anyone could tell the difference between two well-bled systems - one hand-bled (like you describe) and one pressure-bled.
10psi is NOT going to force air into the fluid. The extra water, because of the higher pressure? I'd love to see REAL test data for that claim.
Bottom line - pressure-bleeding works great, and it's much better than vacuum bleeding. And you can do it solo.
The difference between atmospheric pressure and that plus 10psi, especially with the water content of the air, just isn't enough to think about, when talking about how hydroscopic brake fluid is.
I doubt anyone could tell the difference between two well-bled systems - one hand-bled (like you describe) and one pressure-bled.
10psi is NOT going to force air into the fluid. The extra water, because of the higher pressure? I'd love to see REAL test data for that claim.
Bottom line - pressure-bleeding works great, and it's much better than vacuum bleeding. And you can do it solo.
06-16-2007, 11:07 AM
#6
I've bled with pressure, vacuum, and feet. No discernable difference on street or track.
The only discernable difference: pressure bleeding is 10x easier than the other methods.
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06-16-2007, 10:40 PM
#8
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My pressure bleeder creates high pressure in the bottle which...
forces brake fluid out of the bottle, through the pickup tube, and into the master cylinder.
I'm not aerating the liquid, only using air pressure to force it through the system.
I'm not aerating the liquid, only using air pressure to force it through the system.
06-17-2007, 10:56 AM
#10
He knows that. He is saying that, based on Henry's Law, the pressure is...
pushing air and moisture into the brake fluid as dissolved gas and moisture.
As SilberUrS6 suggests a) this can't be very much and b) where is the data to support this. Kday's empirical data says there is no real differences - except that pressure bleeding is WAAY easier and faster.
As SilberUrS6 suggests a) this can't be very much and b) where is the data to support this. Kday's empirical data says there is no real differences - except that pressure bleeding is WAAY easier and faster.