Pull a vacuum on brake fluid?

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I recently did a brake fluid flush and feel the pedal could be a little firmer.

I had previously heard about the Phoenix Systems reverse brake bleeder and was wondering if I could use my brake bleeding adapter cap together with my Mityvac to achieve something similar and pull any remaining air out of the system.

Here is a link where somebody used the reverse brake bleeder to get air out that apparently wasn't bleeding out after multiple regular brake bleeding attempts.

http://forums.pelicanparts.com/porsche-9...lts-beware.html

Thoughts? Seeing I've done the brake fluid change, can I achieve something simiilar just by pulling a vacuum?
 
I have a small hand held vacuum brake bleeder. You have to first back the bleeders out and put some liquid sealant on the threads or they suck air in past the threads. I've found speed bleeders to do the same.

Also I usually start the engine so I have vacuum assist on the brakes when doing the rear as they are usually somehow restricted compared to the front.
 
My method is to put the vacuum bleeder on the caliper, then slowly pump the brakes 10 times. I then remove the vacuum bleeder and let it gravity bleed for a couple seconds to let out any air that made it past the threads of the bleeder. Always results in a nice firm brake pedal.
 
Theoretically, vacuum bleeding is a superior way to draw air out of the lines. Any air grows in volume and is more easily swept away by the process.

In practice, air is drawn past the bleeder screw threads and mucks up the procedure.
 
Originally Posted By: CharlieBauer

I had previously heard about the Phoenix Systems reverse brake bleeder and was wondering if I could use my brake bleeding adapter cap together with my Mityvac to achieve something similar


If you disassemble the master cylinder, you would see that too much vacuum will pull air past the lip on the piston seal - so don't go crazy on it.
 
Originally Posted By: Linctex
Originally Posted By: CharlieBauer

I had previously heard about the Phoenix Systems reverse brake bleeder and was wondering if I could use my brake bleeding adapter cap together with my Mityvac to achieve something similar


If you disassemble the master cylinder, you would see that too much vacuum will pull air past the lip on the piston seal - so don't go crazy on it.
I'm not surprised by this observation. That is why I push the pedal by hand with an airlock at the bleeder. I seal the bleeder threads with some grease. Some time in the process I do a gravity bleed as well. My pedal feels great and I'm smug as all get out because I haven't spent a cent on a tool I don't need.
grin2.gif
 
I've wondered about pulling a vacuum in the fluid reservoir to pull out bubbles, but I'd be afraid to suck extra air in from the bleeders.

I don't know how well it would work on a car, but I've seen motocyclists use a large syringe to inject the brake fluid from the bleeder up to the reservoir, appears to be the same idea as the Phoenix system.

I might have to try something like this next time I do a brake flush, I feel my Element's brakes aren't quite as firm as I think they should be.
 
Originally Posted By: EdwardC


I don't know how well it would work on a car, but I've seen motocyclists use a large syringe to inject the brake fluid from the bleeder up to the reservoir, appears to be the same idea as the Phoenix system.



Works very well on my car, though I've been told somewhere on here that it's wicked and wrong and flying in the face of established good practice.

I think the concerns are that you might squirt some dirt into the master cylinder, or that you might evert seals in the master cylinder. I remove a bit of fluid from the caliper/brake cylinder first to minimise the first issue.
 
I figure, I kinda need the vacuum pump, so as to empty the MC when changing brake fluid. I could steal the turkey baster but the wife gets mad when I return it, no matter how well I clean it. Thus I just live with air bubbles when pulling fluid through the bleeders. In practice it doesn't seem to do anything bad.

I've replaced a few calipers and used the pump, and it seems to work fine for getting the system working. I know gravity would work too but the pump is faster.
 
Originally Posted By: mightymousetech
My method is to put the vacuum bleeder on the caliper, then slowly pump the brakes 10 times. I then remove the vacuum bleeder and let it gravity bleed for a couple seconds to let out any air that made it past the threads of the bleeder. Always results in a nice firm brake pedal.


+1 I always vacuum and then finish off with gravity. Makes for a very nice firm pedal every single time.
 
Originally Posted By: supton
I figure, I kinda need the vacuum pump, so as to empty the MC when changing brake fluid.


Syringe does that too.
 
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