[Shotimes] re;A/C problems on a '95

[Kevin & Cheryl Airth]

James:
 I would recommend to NOT put any leak detector or sealer in your system.
Especially if you are going to keep the car. I use soapy water at the
connections after putting a can in for testing purposes. Or use a Freon
sniffer. I am sending you the 95 Helm charts for R134a. One thing with a
conversion. Your A/C sounds cold enough but you need to adjust the low
pressure switch to about 22 psi for max cooling with R134a. Fords have an
adjustable switch. Take the electrical plug off and you should see the
adjusting screw. With R12 don't go lower than about 28-30 psi. With R12 the
evaporator pressure is almost equal to the evaporator temperature in
Fahrenheit so you want to stay above freezing to prevent ice forming on the
core. System should take 32 oz of R134a and 7 oz of PAG oil if everything is
totally empty.

 Leaks are from the o-rings but on the SHO check the steel lines under the
battery very closely. The battery acid eats holes in the steel lines and
with the foam covering on the tubing it is very hard to see. Our cars are
now old enough to make this a common problem. The small liquid line is
pretty cheap but the large line requires the accumulator/dryer to be
changed. Which is a good idea on any car over 100K miles!
.
.
.



> Been having a little trouble with the A/C on the '95MTX.
>
> My Helms is a '93 and though it mentions A/C systems using R-134a, it
> doesn't give any specifications.
>
> Wondering what the full charge would be from a 25# vacuume?  And what the
> high and low pressures should be?
>
> I got back from Kansas City Thursday night after the "business trip from
> HELL", and to add to my pain, the A/C on the '95 went further South and
> hotter than Kansas City!  I left 100+ weather to get to 80+ weather, but
no
> A/C!
>
> Pressure was zip, when I put my gauges on it today.  So, I attached my
> niffty little air powered vacuume pump and sucked a 25# vacuume, threw a
12
> oz. can of R-134a in and the pressure seemed to hold while I went to AZ to
> get another 12 oz. can of R-134a and a 4 oz. can of sealer/dye.
>
> I now have 44 degree cold air, which is about were it had been for quite
> some time, but who knows how long this will last?
>
> Where should I start looking for leaks?
>
> What is the full charge of this system from a vacuume?
>
> The Helms says that a '93 should take 40 oz +/- 2of R-12, but that seems
> like a lot!  Could it be an error?
>
> What should the high and low presure read?
>
> I left it at 35# low and 270# high getting 44 degree air on a 88+ degree
> day.
>
> Assuming that I find the leak, repair it, what should the pressures be?
>
> regards, Jim White - greensho@crown.net
> Valparaiso, Indiana
> '93  5 SPEED   283k few mods
> '95  5 SPEED   256k lots of mods