R12 Vacuum

[44SAA]

Started to pull vacuum on my OEM R12 system and noticed the valve on the high side is a smaller diameter than the low side valve. As a result my R12 dual gage can’t fit on the high side valve. Can I just pull vacuum using the low side only? Thank you

[Ziegelsteinfaust]

Yes it is just not as fast.

[Katrina/10]

You'll need a high-side adapter to use both gauges. They are still available.

[44SAA]

While the threads on my yellow jacket R12 gauge fit on the low side- the schraeder valve on the low side isn’t being depressed by the valve on gauge set. Katrina- is this the adapter you are speaking of. Kinda frustrated as I bough the yellow jacket gauge set labeled R12 as I figured it would hook right up? Thank you

[Katrina/10]

The high side adapter looks like this: https://www.ebay.com/itm/153812368295

You attach it to the evaporator inlet then screw on your yellow jacket hose.

If you get no pressure reading on the gauge, there is something wrong with the valve or hose. Or, no refrigerant.

[Just call me Sean]

The blue line hooks there. Looks like you have the yellow in your hand.

[Corts60]

Originally Posted by Just call me Sean

The blue line hooks there. Looks like you have the yellow in your hand.

Yep. Yellow one goes to the vacuum pump. Are you using a micron gauge to tell how far down you are pulling the system?

[44SAA]

Originally Posted by Corts60

Yep. Yellow one goes to the vacuum pump. Are you using a micron gauge to tell how far down you are pulling the system?

Hey Corts- not sure what a micron gauge is. I posted a picture of the gauge I am attempting to use. Thanks

[44SAA]

Thank you. I realize the yellow hooks up to the vacuum pump and the blue to low side. I just posted that pic to show the fitting that will not engage the schraeder valve as it is identical to the blue hose fitting. Thank y’all for the help. It’s been frustrating.