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General Tech Bleeding Brakes—Venturi/Compressor

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KVH

KVH

Obi Wan
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I have one of those old Griot’s garage one man bleeder kits that you use with a compressor. When I use it, I never see an end to the bubbles. In other words, I don’t get to a point where everything just looks like clear fluid coming through the plastic line.

Can anyone just give me a little thumbnail description of how that tool is effectively used, and whether it is still considered a good tool. I see so many others out there.

Thank you
 
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Sorry, I don't know how that particular brake bleeder works, but I've always managed to bleed brakes by myself using the gravity method. With as far along as you are with the bleeding, it should be a breeze to finish by gravity bleeding.
 
I do know that if you open the bleeders too much they will suck air. So the air is not from the system, but introduced through the bleeder screw threads. Only crack the bleeders just enough to get a flow, no more, and the bubbles should stop.
 
I use a tall glass jar filled about half way with brake fluid. I run a clear hose from the bleeder to the bottle with hose clipped to jar to keep fom popping out. Hose is long enough i can see from drivers door. I open bleeder and pump brakes and watch bubbles. Fluid when pumped might return to cylinder but air goes to the top of jar and out. Used one man bleeders, but can be messy. Have not seen Griots, but have used similar.
 
CJD said:
I do know that if you open the bleeders too much they will suck air. So the air is not from the system, but introduced through the bleeder screw threads. Only crack the bleeders just enough to get a flow, no more, and the bubbles should stop.
Click to expand...

+1. Also note that the bubbles are generated at the bleeder screw so the air may still be evacuated from the system even when you see the bubbles. At least that's what I've found with my vac bleeder.
Tom
 
One alternative is to wrap the bleeder threads with Teflon tape to better seal against the ingress of air as you vacuum bleed.

I have used the venturi sucking unit from HF (looks like the Griots version) but for easy bleeding I usually go with a pressure bleeder made from a bicycle inner tube. Quick, easy and effective.
 
Thanks guys. I finally got everything working fine. I had a terrible time bleeding those lines, and maybe because so much air was caught in the lines from when I put the car on jacks two months ago with the fluids empty.

I eventually used the old fashioned way—my son pumping the brakes, but it literally took over an hour of going back and forth thru the process until my rear cylinders would finally bleed.

So, naturally, I’m wondering if it was all my fault, and I have two questions.

First, did I mess up by not bench bleeding the master cylinder. I can’t recall ever needing to do that when I replaced the brake master cylinder in the past. It always seems the bleeding process took care of that.

Second, when I was all done I noticed that the emergency brake was partially on. Could that have been part of the problem? (Should I have publicly admitted doing this)
 
Those master cylinders often get air bound. Bench bleeding will avoid that. So will cracking the pressure line at the cylinder itself while pumping after it's in the car. Not a problem with a vacuum or pressure bleeder though.
Although the hand brake will limit the movement of the pistons in the wheel cylinders, you still should be able to get rid of the air.
Tom
 
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