16 hours?
Are you wanting to suck the hoses flat too?
Not needed this long to evacuate.
The most should take with worn out old pump, maybe 1 hour.
New O-rings are needed anytime system is opened at fittings.
Just a better job, no leaks.

Good Afternoon,

E-mail message

Steve, thank you for your reply. I reused the old O-rings as they were
tight. I put it in my question just in case reuse of the O-rings was a
non-no.
Right now, I have had the system pumping down for about 16 hours so it
should be dry by the time I fill it later this afternoon.
John
----- Original Message -----
From: "Steve Cotsford" <Cotsford@AOL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, May 25, 2003 9:42 AM
Subject: Re: How long to pump down A/C ?
Why would you use the old o-rings ?
You can get adaptor kits at Pep Boys quite cheap and the new ones are
bluish-green and work with all the oils you may encounter these days
whereas the old
black ones wont.
I would suggest that you pull the vacuum down for at least 45 mins.
Longer if you can wait.
If you are using a conventional gauge set , then you can open both high
and low side to the center hose, assuming thats where you have the pump
attached. Both sides will show a vacuum reading and I would like to see
at least 28. What kind of pump are you using? � Sounds like a medical
pump. � It maybe worth your while to borrow an automotive a/c pump
which probably wont give any volume values. � Once a good vacuum is
pulled, I doubt if the volume means much.
I borrow a friends'. I dont know what brand it is, he just calls it
Monica,
lol
I have worked on 3 systems this spring, including converting my recently
sold
'84 Westy to R134a. � � � If you want to chat on the phone about
it, I
would
be happy to.
p-mail me for the number.
good luck,
Steve Cotsford
Columbia SC

Fred