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Meh....
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72 Posts
Discussion Starter · #1 ·
I attempted to flush my front brake fluid with a Mity Vac today and inadvertently got air in the brake lines. There is zero resistance on the brake handle. Now I can't seem to be able to suck brake fluid.

What I'm doing:
1. Attaching the clear tube to the closed bleeder valve.
2. Pumping the Mity Vac 5 times or so.
3. Then opening the bleeder valve.

At this point should the clear tube be filling with brake fluid? Mine isn't, I'll get an occassional bubble of fluid going through the tube but that's it.

4. Close the bleeder valve. I know I'm getting suction because when I remove the hose I can hear the vacuum being released.

What can I be doing wrong? Is it possible that I'm opening the bleeder valve too much and its sucking air from around the bleeder valve threads?

Help me out here!!
 

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351 Posts
you've got to bleed the master cylinder... then bleed each side...

I also had to manual pump the brakes and bleed manually to get all the air out... mity vac won't get all the air out of the lines...
 

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yield
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17,823 Posts
I hate my Mityvac... I get my lines vacuum bled at my local dealer. That shit leaked, got all over the place, and despite my greatest efforts I couldn't get it to work efficiently- lame
 

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Beave said:
How does one bleed the master cylinder?
There should be a nipple attached to it just like the ones on the calipers... If it doesn't, your gonna have to crack open the banjo bolt that attaches to it.... Be for warned make sure you have lots of rags underneath it and wipe up all spills ASAP...
 

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EDAWG
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156 Posts
I did mine about 2 weeks ago and did it manually.. have one extra set of hands to open and close each side in between pumps..

e.g. pump and hold lever.. open and close bleeder valve for each caliper...

I used 2 clear hoses and a connecting 2 in 1 out adapter into a bucket.. worked awesome.. my brakes have never been as tight as they are now.. :dunno

easy, cheap, just as fast as wrestling with a vac... just my .02 though..
 

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see you at the races and ride
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the 98-03 MC's don't have the bleeder. You could try pushing the pistons back in to push fluid back thru the master cylinder. Once a little firmness is felt you can loosen the banjo fitting onthe MC to expel any trapped air. I just use a 2 oz. syringe to fill and bleed.
 

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EDAWG
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156 Posts
The master cylin. piston is the round piece which is typically pushed in by your lever. You can use a flat head to do it manually if your lever is not getting it all the way in.. that's what i did to get that little extra pressure on the lines.. The other thing to note is to leave your calipers straight up and down so the air flows up and out the top of the bleeder valve..
 

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see you at the races and ride
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Beave said:
Sorry for another dumb question but where is the master cylinder piston? And what is the best way to push it in?
I meant push all the CALIPER pistons in thus pushing the air out of the master cylinder.
 

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I Jigga high, I Jigga Lo
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1,709 Posts
I love my mity-vac.

Open resevior cap and have a homie pour fresh brake fluid in resevior as you suck from the bleeder nipple. You are in essence flushing the system at this point. Basically, you have to take the fluid cap off and not allow air to be sucked in at resevior level, just fresh fluid.
 

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Meh....
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72 Posts
Discussion Starter · #15 ·
Thanks guys, there apparently was air in the master cylinder somewhere and after loosening the banjo bolt and pumping brake lever it worked its way out.

Thanks again for the help.

Ride safe :)
 
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