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Easy ways...Re: A/C DIY? Posted by vtsnaab [Email]  (#26)  [Profile/Gallery]
(more from vtsnaab) on Mon, 14 Apr 2008 22:04:33
In Reply to: Re: A/C DIY?, yaofeng, Mon, 14 Apr 2008 20:04:13 Members do not see ads below this line. - Help Keep This Site Online - Signup |
My '91 had a busted a/c hose and there was no rebuilding shop around, nor
anyplace within 150 miles to rent a vac pump.
Gauges I've always had since I serviced rooftop HVAC years back but no
stuff for the 134a conversion...
Here's how I solved all of it:
The hose new cost over $175, but I had a slightly different one hanging
around with the same threaded end - so I cut 'em both a bit long, coated
the aluminium end with Leak Lock blue and jammed it in as far as absolutely
possible - then secured it with 3 SS clamps and reconnected it.
(Leak Lock info: http://www.highsidechem.com/leaklck.html )
MOST IMPORTANTLY:
I am hoping you already know how a/c works and the difference between
the high and low sides and what is done with them, if not, get better
info than my post before starting to do this or you'll be at risk and
that is a BAD idea.
Back to the stuff now...
The need of a vac pump was easy enough - since I have a 150 PSI air
compressor I just picked up an old-style Air-Vac venturi deal off
fleabay for under $30 - the newer kind is a Robinair ROB34970, but
I wanted the older metal box kind instead of the cast plastic one;
if interested, just search for air+vacuum+pump and you'll always
see like 30-50 on sale to choose from there.
Then what is needed is an r134a adapter set - and if you search
for 'R-12 R134A AC Adapter Hose Fitting Tool Set' you'll see there's
a nice set for $18 and $9 shipping.
Gauges are easy too, just search for 'ac manifold gauges' and you'll
even find new ones for under $40 shipped, with standard r-12 shrader
type ends, which is what the adaptors are for...
R-134a can be had almost anyplace and I usually just get cans of that
and the oil at Kmart pretty cheaply, and use the enclosed hose to
connect to the middle of my guage set instead of the long yellow one.
For R-12 cars, they usually don't have any freon left in them, and my
POV is just to change out the bad parts, vac it down and make sure it
holds a steady vac with valves shut for 15-30 minutes, then in goes
the oil and gas charge (best on a warm-ish day to see a good range of
pressures...); tighten it up and you're done.
R134a is generally easier than older refrigerants to work with in my
experience and I've had good luck with it.
Bear in mind that over-charging can be dangerous and that there is no
such a thing as too deep a vacuum - so if you want to vac it down for
quite a while to make sure any 'hidden' air pockets are sucked down
really well, go for it because that is better than air pockets in the
freon afterwards.
R134a uses lower high-side pressures than the r12 scale shows and a
good way to get an idea of the relative pressures needed is to read
a cheapie tire-style gauge package anyplace they are sold; the gauges
aren't so good, but the pressure info on the package is OK as a guide.
All this is outlined well at:
http://www.firstfives.org/faq/AC/ac_charge.html
I hope any of that is a help for you !
mark
, Mon, 14 Apr 2008 22:04:33 <-- Viewing This Message, Wed, 16 Apr 2008 22:32:58, Thu, 17 Apr 2008 22:39:08
, Fri, 18 Apr 2008 11:33:33, Tue, 15 Apr 2008 11:09:31
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