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MityVac - Bubble In The Line

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GregH

GregH

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I bought a MityVac and used it last Saturday to flush and bleed the brake lines. It was my first time and all went well except that I had bubbles streaming in from the bleeder valve. The MityVac site says the bubbles are either from the hose not being tight enough (could be) or air being pulled in around the threads of the bleeder valve screw (likely). They suggest using teflon tape around the screw threads to tighten it up.

My concern is having pieces of the teflon tape getting into the brake assembly. Has anyone ever done this? Was I simply loosening the bleeder valve more than needed?

(BTW, the brakes are working great. Nice and tight.)
 
Next time try not loosening the bleeder as much. I found that helped. I'll admit though that on the bikes that were a pain to bleed I switched to speed bleeders and life was good.
 
GregH said:
They suggest using teflon tape around the screw threads to tighten it up.
Click to expand...

That's what I ended up doing. Just be careful when you're wrapping the bleeder not to use too much and you should be fine.

trey
 
GregH said:
My concern is having pieces of the teflon tape getting into the brake assembly.
Click to expand...

On an ABS system I would be very careful. On a non-ABS I will not worry for using a little bit, just do not go crazy with it.

I used to use it on $200,000 Down Hole Hydraulic Drilling Tools and never had problems because of it.
 
The idea behind the vacume bleeder is to speed up the process which it does very well . The bleeder screw is not designed to seal at the threads , it seals at the bottom so there is no surefire way to seal the threads . suck the fluid thru the system with the vacume bleeder then top off the master cyl then pump the lever , hold and tighten the bleeder a couple times . That will assure that no air is in the slave cylinder . Nothing like doing things the old fashion way every now and then . SEYA
 
Don't worry about it. The air is coming through the threads and straight out of the bleeder nipple. It is not being sucked back into the brake line. As noted, Speed Bleeders are cheap and an excellent add on for us lazy people. Bill will be along shortly to tell you you don't need either. :trust:
 
I borrowed a Mity-Vac once, but wasn't all that impressed. I've had better luck doing it the "old fashioned" way.

I have heard of squeezing the lever with a rubber band or zip tie overnight will supposedly work air out of the system, but I haven't tested it myself and I haven't figured out the logic of how that allows air to escape the system. Seems to me it would still have to get past the master cylinder cup. :shrug:
 
No help on this issue, I know.

But, when starting with a completely dry system, like when upgrading to steel lines, the Mity Vac is a godsend. Pulled fluid into the system instantly.
 
I do plan to put on steel-braided lines at some point in the not-too-distant future.

I like the MityVac because it really does pull. Even with air leaking around the threads I was able to flush the lines in less than 5 minutes. I wonder how fast it will go when I seal up the bleeder valve threads...
 
It will take longer to seal the threads than to just bleed the brakes . If you just have to seal the threads use a product that will control corrision after the slave cyl is sealed up so the next time you flush the brakes there will be no bleeder screw problums . I have never reserched a sealant product that is compatible with brake fluid , your on your own there . SEYA
 
The SpeedBleeder site sells a liquid material used to coat the threads of the bleeder screw. I'm wondering what is in it. I'll give my auto mechanic a call.
 
The rubber band on the lever overnight works. Bleed the old fashion way several times - then apply the rubber band with good pressure on the lever.
Next morning just loosen the bleeder screw a very small amount and the final air bubble will come out and you should be good to go.
Been doing this for years on my bikes.
I have never done it on a bike the ABS systems so I can't speak to that.

Ron
 
thumper_tx said:
The rubber band on the lever overnight works. Bleed the old fashion way several times - then apply the rubber band with good pressure on the lever.
Next morning just loosen the bleeder screw a very small amount and the final air bubble will come out and you should be good to go.
Been doing this for years on my bikes.
I have never done it on a bike the ABS systems so I can't speak to that.

Ron
Click to expand...
Thanks for the clarification. I missed the last part about a final bleed cycle.
 
patricjft said:
No help on this issue, I know.

But, when starting with a completely dry system, like when upgrading to steel lines, the Mity Vac is a godsend. Pulled fluid into the system instantly.
Click to expand...

Its also great for changing out your fluid every couple years. A real time saver.
 
Trust me! Bleeder valves seal based on a tapered (Flare) fitting! No teflon tape needed!
Oh yes, you "MAY" have a leak... But my guess is that you have solidified brake fluid in your system. Just an offer to help, based on experiance!
CAF
 
When I added my Rekluse left hand rear brake on my green E, the kit came with a large syringe and hose for reverse filling from the brake cylinder. It worked great and required no extra bleeding. You start with a brake cylinder already full (or the bleeder valve is at the bottom) and be sure that the syring/hose has absolutely no air bubbles when you start the process. I'd never filled a brake system this way and was surprised how well it worked.
 
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