brake bleeding with vacuum?
 

I just bought a vacuum pump from autozone. The directions are sketchy and
I have never used one, so do I pump before I open the bleeder valve or start
pumpng after I open the valve? Thanks for any reply.

I usually pump mine up before opening the valve to build up the pressure.

pump before you open it.

If you only crack the valve open a little then it doesn't
matter, the fluid doesn't go anywhere. Too far open and
you will just suck air through the threads. I've had the
best luck with only 1/2 - 1 turn off the seat. It takes a
lot of pumping & time to draw all the old brown glop
through. I made a "catch can" of a glass jar so I could
see better when it changes color (your vinyl tubing will
age pretty badly once it sees brake fluid).

how much did you spend?
I bought something like that a while ago, cost $10. Never used it because it was mickey mouse and will end up throwing it out.
If you want to use it, and it's a vacuum bleeder hooking up to the caliper bleeder screw, you pump it first so there's vacuum in the jar so when you loosen the bleeder screw no air goes into your caliper. That is the purpose of it, and it sort of sucks when considering if you're flushing your system or want to run a good amount of brake fluid through the caliper. The container I had held 8 ounces at best. I just did my brakes and changed to braided lines at the caliper, I went through 3 qts of dot3. You want to opening and pour brake fluid as little as possible because of the risk to paint.
I used earl's solo-bleeds and they are great, don't need anything but vinyl tubing from the solo-bleed screws to a jar or coffee can. Other than that, the only other practical and sure way is to use a pressure bleeder which sits atop the master cylinder and forces brake fluid through the system.