The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 09-05-2021, 08:28 PM   #1
44SAA
Registered User
 
Join Date: Apr 2017
Location: Fort Worth
Posts: 78
R12 Vacuum

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 canít fit on the high side valve. Can I just pull vacuum using the low side only? Thank you
Attached Images
 
44SAA is offline   Reply With Quote
Old 09-05-2021, 08:37 PM   #2
Ziegelsteinfaust
Registered User
 
Join Date: Dec 2012
Location: Temple City
Posts: 2,785
Re: R12 Vacuum

Yes it is just not as fast.
Ziegelsteinfaust is offline   Reply With Quote
Old 09-06-2021, 08:23 AM   #3
Katrina/10
Registered User
 
Katrina/10's Avatar
 
Join Date: Oct 2010
Location: Ocean Springs, MS
Posts: 1,741
Re: R12 Vacuum

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

1971 Chevrolet C/10
1951 GMC 100
1977 GMC C15
1955 Chevrolet 3100
Katrina/10 is offline   Reply With Quote
Old 09-06-2021, 12:27 PM   #4
44SAA
Registered User
 
Join Date: Apr 2017
Location: Fort Worth
Posts: 78
Re: R12 Vacuum

While the threads on my yellow jacket R12 gauge fit on the low side- the schraeder valve on the low side isnít 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
Attached Images
  

Last edited by 44SAA; 09-06-2021 at 12:47 PM. Reason: Photo
44SAA is offline   Reply With Quote
Old 09-06-2021, 01:04 PM   #5
Katrina/10
Registered User
 
Katrina/10's Avatar
 
Join Date: Oct 2010
Location: Ocean Springs, MS
Posts: 1,741
Re: R12 Vacuum

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.
__________________
Gary

1971 Chevrolet C/10
1951 GMC 100
1977 GMC C15
1955 Chevrolet 3100
Katrina/10 is offline   Reply With Quote
Old 09-06-2021, 02:32 PM   #6
Just call me Sean
Registered User
 
Just call me Sean's Avatar
 
Join Date: Jun 2014
Location: Orlando Florida
Posts: 860
Re: R12 Vacuum

The blue line hooks there. Looks like you have the yellow in your hand.
__________________
Quote:
Originally Posted by Early Cuyler
Fights begin, fingerprints are took, days is lost, bail is made, court dates are ignored, cycle is repeated.
Just call me Sean is offline   Reply With Quote
Old 09-06-2021, 06:03 PM   #7
Corts60
Just here to tinker
 
Corts60's Avatar
 
Join Date: Jun 2008
Location: Holland, MI
Posts: 3,329
Re: R12 Vacuum

Quote:
Originally Posted by Just call me Sean View Post
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?
Corts60 is offline   Reply With Quote
Old 09-06-2021, 06:15 PM   #8
44SAA
Registered User
 
Join Date: Apr 2017
Location: Fort Worth
Posts: 78
Re: R12 Vacuum

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.
44SAA is offline   Reply With Quote
Old 09-06-2021, 06:26 PM   #9
44SAA
Registered User
 
Join Date: Apr 2017
Location: Fort Worth
Posts: 78
Re: R12 Vacuum

Quote:
Originally Posted by Corts60 View Post
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 is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:06 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Copyright 1997-2020 67-72chevytrucks.com