Build your own vacuum test station so you can accurately test valve bodies, check balls in cases and pistons, sleeves and bushings in automatic transmissions. You can get vacuum test guides for free from www.sonnax.com. If Sonnax sells a replacement valve, they usually share a typical specification for the vacuum test. Just go to the valve and open the instructions or click on the link that says “you need this if.”
Vacuum testing has been around for many years and I’m still surprised to hear that some shops still don’t check the valve body and transmission for wear using a vacuum test stand. It’s simple and repeatable. It’s one of those tools that answers the question “could this have caused the failure.” Without it, it’s really guess work.

The following are parts found on Amazon.com that were included in this video. I’m sure you can find many, if not all, of the components at your local hardware store and auto parts store. If you have a harbor freight close to you, you can get the vacuum pump pretty cheap (especially if you have one of those 20% off coupons)!

Vacuum gauge: https://www.amazon.com/UHARBOURGlyce...

Needle valve: https://www.amazon.com/LASCO171901...

Push fittings: https://www.amazon.com/PneumaticPlus...

¼” tubing: https://www.amazon.com/PneumaticMete...

Brass tee: https://www.amazon.com/LeginesBrass...

1/8” npt nipples and couplers: https://www.amazon.com/GasherMetals...

Vacuum pump: https://www.amazon.com/ZENYSingleSt...

Welding tip cleaner (for drill bits): https://www.amazon.com/LincolnElectr...