I've used a MityVac for years to bleed my brakes and it works very well after you make a few modifications.
First, as mentioned above there is no easy way to seal the leak around the bleeder screw with grease. But there is an easy way to seal it off, nontheless.
I called a pigtail and it consists of a bleeder screw with 1/4" trimmed off the pointy end. A small length of 1/4" tubing secured with some wire to the end of the 1/4" tubing and a rubber washer on the threaded part of the bleeder screw. Screw this into the brake cylinder and you will have a perfect seal. All the parts are readily available at Lowes or Home Depot. With the exception of the bleeder screw. You can get them at any auto supply store.
The other thing that needs to be made is a way to keep from sucking air back in the lines. That's easy as well, with some of that spare tubing, and a old mayonaise jar.
I went full Adam Savage on this over at ToyotaNation. You can read through the entire thread if you want to track the progress of the build. I think it works as good as any of the commercial ones, and it didn't cost a lot to build, and I got a kick out of making it.
As they say, if it's worth doing, it's worth overdoing.
https://www.toyotanation.com/forum/...der-bleed-your-brakes-easy-way-many-pics.html
I cobbled this all together back in 2010, and it still works just fine even today. Matter of fact, I just used it a month ago to bleed a friends brakes.
I guess you could buy one, but what's the fun in that?
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