Brake bleeding with a Mity-Vac


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SilverDave
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Brake bleeding with a Mity-Vac

Postby SilverDave » Mon Aug 22, 2011 11:41 am



I just finished a caliper re-build on my ( Classic) GL1200 and tried for a half hour to bleed the three brakes.
I was using a new to me Mity Vac... and I kept getting bubbles , which on closer inspection appeared to be from the very tip of the clear tygon tubing .... I snipped it off twice to get a clean end ...
????
Eventually I gave up, and bled them by the old fashioned method ... with a glass jar, and arched clear tygon hose... took about 15 minutes... and all three are hard as a rock...

But....
Am I missing something here ? a mity vac should suck fluid out of the caliper, even faster ... Is there a trick to attaching it to the brake nipple ??? ... so that bubbles are not formed ???

SilverDave



dan1951
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Re: Brake bleeding with a Mity-Vac

Postby dan1951 » Mon Aug 22, 2011 2:03 pm

Your Mity-vac should have came with various bleeder screw adapters that attach to the end of the clear hose that attaches to the collection vial. Press on the end of bleeder screw, pump up the vac 10-15 times until fluid enters the collection vial tighten screw, refill master cylinder And repeat until fluid runs clear of bubbles, Keep a eye on fluid level in master cylinder, I use Mine quite abit and it works good, I would not say it works that much faster but seems far easier when Your working by Yourself.

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SilverDave
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Re: Brake bleeding with a Mity-Vac

Postby SilverDave » Wed Aug 24, 2011 4:15 pm

Well that puzzle took a while :
my mechanical friend came over, and showed me

.... the NEW Mity Vac I have, along with 25 year old brake nipples, has enough suction to suck air past the ( possibly worn ) threads, and into the tygon tubing...

I can use it, but I have to just barely crack the bleed valve , just a hair, so that no air is sucked past the threads ... I possibly need a way to turn the vacuum "down" by a controlled amount. I know there is nothing ( except brake fluid ) that one can put on the threads to prevent this leak of air ..

Hmmmmm...
SilverDave

dan1951
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Re: Brake bleeding with a Mity-Vac

Postby dan1951 » Wed Aug 24, 2011 10:09 pm

I was curious, So I got the user,s manual out so if I ever run into the same problem. It does have a note about air leaking around threads the manual MV8000 page 22 says to use teflon tape on the thread portion only of the bleed screw. Dan

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feetup
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Re: Brake bleeding with a Mity-Vac

Postby feetup » Thu Aug 25, 2011 1:34 pm

Take the bleeder screw right out and clean the nipple end up with a fine wire wheel or the like so that the hose fits cleanly, and clean the threads free of all rust and dirt. If using a wire wheel stay away from the sealing taper, and place a loose towel under the wheel to catch the bleeder as the wheel fings it at the ground.
Then run a few wraps of teflon tape tightly around the threaded portion. Hold the bleeder in your left hand and wrap over the top, away from you so that tightening the thread tightens the tape as well. When you have 3 or 4 wraps of tape take a sharp utility knife or scalple and cut the tape at the end of the threads leaving the bleed hole clear.
Re-instal and use your vacuum bleeder. I use an electric pump which produces nearly 15 lbs of vacuum and get no air bybass.
Alternately there are aftermarket bleeders with o-rings just below the threads, but I find the teflon tape works even better since the threads on the gold-wing calipers go quite deep and the o-ring will not seal against the threads.

danny1
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Re: Brake bleeding with a Mity-Vac

Postby danny1 » Tue Nov 08, 2011 11:47 am

Get rid of the mityvac and buy a cheep oil can with a pump on it. Put a hose on the end if the tube connect to bleeder valve take cap off master cyl and pump away. Its quick and you are not trying to suck air bubbles downward. Plus you save a lot of money pump can should be no more than $10-15 dollars.

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upssnowman
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Re: Brake bleeding with a Mity-Vac

Postby upssnowman » Sun Nov 13, 2011 6:28 pm

Personally I just don't worry about the bubbles, fluid is being pulled down the lines and out past pistions so just don't worry about the small amount of bubbles being leaking around tube ending or threads , this is past the point of concern anyhow.
after using the MV to suck new fluid down the line ALWAYS pump up and crack the bleeder the old way, anyhow this hould always be the finishing step.
This gives the really firm petal
just my experience.

danny1
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Re: Brake bleeding with a Mity-Vac

Postby danny1 » Sun Nov 13, 2011 7:08 pm

I understand what you are saying but I have found that when there is a tee fitting in the line air can be trapped and cause a problem. When you use my method the air is forced up and past the tee. There is also the problem when brake lines run from the master and get routed with a section tilting upward air can linger ther also. I have used both methods and find that the oil can route saves time and headaches.

Paradise97401
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Re: Brake bleeding with a Mity-Vac

Postby Paradise97401 » Thu Dec 01, 2011 2:02 pm

I have done away with all that..and just installed speed bleeders to all of my bikes, they are a one way check valve, so you just crack them open and pump the fluid till the air is out and close them.

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CharlaineC
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Re: Brake bleeding with a Mity-Vac

Postby CharlaineC » Sun Jul 15, 2012 9:33 am

where can i order the speed bleeding valves or at leastva new bleeder valve my front valve left break valve seems to be allowing air into the lines i pit put my vac bleeder on and pump her to 15 pounds and shes drawing fluid out of the lines before shes even opened. the hoses are tight and clesned

Paradise97401
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Re: Brake bleeding with a Mity-Vac

Postby Paradise97401 » Sun Jul 15, 2012 6:51 pm





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