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CMR 11-30-2009 12:26 PM

Vacuum pump to bleed brakes
Has anyone ever tried anything like this before? Do any of you think it would work? Also does anyone have an idea for what kind of pump I could use? I was thinking I might use an electric fuel pump. It could even run off the battery. Or if someone could tell me where to buy a small 12v pump cheap that would be cool too. Thanks.

JaggedEdge 11-30-2009 07:48 PM

I have used a hand operated vacuum pump to bleed brakes many times. The brand (I think) is Mighty Vac. It is a hand operated piston pump with a small catch can that captures fluid. Has a rubber hose that fits over the bleeder.
You just crank the handle a couple times to pre-vac... open the bleeder and pump till the canister is full. Close the bleeder... then you can empty the canister and start over.
I know after using it I will NEVER go back to the two-man method. I also never had much luck with gravity bleeding.
I do know you have to be watchful you don't suck the reservoir dry as this thing is fast.
I believe you can get one at most parts houses and if I remember it was pretty cheap.
You can also use it for other things like testing vacuum advance on a distributor...ect.

marzini 11-30-2009 08:27 PM

Exactly as JaggedEdge said itó it is the way to go and it's very easy to use!

Dave57210 11-30-2009 08:29 PM

Vacuum bleeding
As an additional note - the way you have it shown in the diagram puts the old brake fluid back into the master cyl. DO NOT DO THIS! EVER!

The stuff you get outta the lines is NOT to be reused. Brake fluid is not very expensive, but your life is - so is your car. Do not take chances with the brakes.

In fact, flush the entire system every year or so, replacing all the fluid with fresh new stuff (ask me how I know what happens when you don't! Hint - it involved a brake line that rusted through from the INSIDE due to moisture collecting in one spot)

oldred 11-30-2009 08:38 PM

DON'T buy one of those pumps from Harbor Freight! That is one of the items they have that would be a rip-off if they were giving them away free! I bought one of the junky things and it only worked for a few minutes then just simply quit pumping, when I took it apart to see what was wrong the problem was obvious. The piston was waaaaay too small for the bore, so small in fact that the seal just barely touched the walls of the bore all the way around so they had packed the dang thing with heavy grease to make it seal. As soon as the grease was dissolved, which will occur with almost anything you might pump except water, it would quit working completely. I would say it quit sucking but that dang thing sucks big time, just in the wrong manner! :mad:

61bone 12-01-2009 08:36 AM

Amen to the never reusing brake fluid. Even if you just overfill the reservoir, don't put it back in the can.
I have two types of vac bleeders. one manual (mighty vac), one air powered. neither was expensive and both work well. For those problem child systems that have high spots in the lines or need a flush, I use a pressure bleeder that runs under 60 psi. Quick, reliable, easy flush and bleed, but boy what a mess. Takes a bag of floordri and an hour to clean the shop.

302 Z28 12-01-2009 09:08 AM

Any vacuum pump can be used. The key is to make a jar or bottle with two ports in the lid. One port attaches to your vacuum pump and the other goes to the brake bleeder. This way the fluid collects in the bottom of the jar or bottle and does not go into the vacuum pump.


kleen56 12-01-2009 09:30 AM

I use the MityVac all the time as well. They are great for starting fluid after putting new brake lines in and drawing the fluid to the wheels. I've found that although the MityVac works and gets fluid through the lines, the old fashioned method of pumping the brakes and breaking the bleeders works best, particularly with disc brakes. The Mityvac sucks the fluid, where pumping builds up pressure in the line and pushes the fluid out. The Mity Vac works well if you only have one person as well. Always start from the furthest bleeder and work your way up to the Master cylinder when bleeding each wheel. Keep an eye on your brake fluid as well in the reservoir. If you run out, you get to start all over again. (been there done that!)

oldred 12-01-2009 09:57 AM

Something I do (if someone has a good reason why this is not a good idea please tell me) is remove the bleeder screw and lightly coat the threads with Permatex sealer so that it does not suck air around the threads while vacuum is being applied. I found it works much better this way and there will not be any bubbles in the catch bottle when the air is out of the system, unlike the bubbles you can get from air leaking around the bleeder screw threads even when the air is out of the system.

kleen56 12-01-2009 10:07 AM

This is a first with permatex? however I do use teflon tape on the bleeder threads and that works fine. I think permatex could get messy?

302 Z28 12-01-2009 11:45 AM

The speed bleeders do have some sort of sealant on the threads.


oldred 12-01-2009 02:31 PM

Actually the Permatex is not messy at all, just a little dab on the threads is all it takes since brake fluid doesn't dissolve it.

sixdogs 12-01-2009 03:45 PM

Good thread. I wrestled with two man bleeding for years but will give the MightyVac a try. Wife tired of pushing the pedal anyway.Thanks

stimpy 12-01-2009 09:06 PM

when I worked on the line as a wrench we had problems with the mighty vac pulling air past the seals on some older cars ( mostly fords with the unsupported cups ) I refused to use one after awhile ( either did it the 2 man way or by gravity ) , I just bought a cheap power bleeder ( motive power) for less than $150 from summit and it works great .

pepi 12-01-2009 09:26 PM

see if you would like this ............

I will say this...... the small container that is supplied, the one that holds the brake fluid will not hold a vacuum so you will need to change that somewhat, PM me if interested and I will send you a picture of how I fixed that problem ....... very simple

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