91 Thunderbird Air Conditioner

Tom Adkins wrote:
> Happy Traveler wrote:
>
>> Sorry pal, but in my humble opinion this is bad advice. If the system
>> lost refrigerant, there is a leak that should be addressed. Even
>> ignoring the legal aspect of dumping it into the atmosphere,
>> considering that today's price of R12 is about equal to that of gold,
>> it would be very unwise to recharge a potentially (if not certainly)
>> leaky system. It may also contain moisture, which needs to be
>> evacuated first. And with a vehicle this old, other repairs, like
>> replacing the dryer/accumulator may be needed. Considering the cost of
>> R12, it may be wise to consider converting the system to R134a at this
>> opportunity. Properly done, this will require flushing etc -- again
>> better done by a pro.
>> And incidentally, the recommended (if not the only) way to charge is
>> with the compressor running.
>>
>> "Sharon Cooke" > wrote in message
>> ...
>>
>>> You don't have run the car at all to pressurize the system with R12.
>>> YOUR biggest problem(s) will be find the R12 to buy (without having
>>> an EPA exemption certificate), and an install connector. A pressure
>>> gauge with the correct fitting is also great to have.
>>
>>
>>
> While what you say is true, I think Sharon Cooke was referring to
> pressurizing the system to leak test.

Actually, I was talking about "topping off" the system with R12. Back
when I actively worked on cars for myself and other people, and R12 was
< $1 a 14 oz can, I'd top off the system using a commercial pressure
gauge (after leak testing) to bring the system up to the required low
side pressure at 80º F., WITHOUT having the engine running at all. There
IS NO "magical check valve" in the system that blocks introduction of
refrigerant to the system when it isn't running. As long as the Delta-T
pressure of the supply refrigerant is higher than the system pressure,
the refrigerant will go into the system; you just require the gauge set
to do it that way, with a running check on pressure increases.

BTW, R12 is still available (with an exemption certificate) for maybe
$15 a pound, hardly the price of gold.

No need to bypass the switch. Just add refrigerant and the pressure will quickly come up enough to close the switch.

Jeff DeWitt wrote:
>
> Any shop that does AC work should be familiar with the system and be
> able to add refrigerant. I believe they bypass the cutout switch while
> charging the system.

--
Mike Walsh
West Palm Beach, Florida, U.S.A.

Sharon Cooke wrote:
>
> Actually, I was talking about "topping off" the system with R12. Back
> when I actively worked on cars for myself and other people, and R12 was
> < $1 a 14 oz can, I'd top off the system using a commercial pressure
> gauge (after leak testing) to bring the system up to the required low
> side pressure at 80º F., WITHOUT having the engine running at all. There
> IS NO "magical check valve" in the system that blocks introduction of
> refrigerant to the system when it isn't running. As long as the Delta-T
> pressure of the supply refrigerant is higher than the system pressure,
> the refrigerant will go into the system; you just require the gauge set
> to do it that way, with a running check on pressure increases.
>
> BTW, R12 is still available (with an exemption certificate) for maybe
> $15 a pound, hardly the price of gold.

I stand corrected. I didn't realize you were talking about that method. Yes, it does
work.
I will take exception with you about "topping off" an R-12 system though. If the
system has a leak, it really doesn't make financial sense unless you have a supply on
hand and are doing it yourself. Shops are charging $25-40/lb in my area, and the 1lb
cans still generally sell for that price. It seems like a waste.
R-12 is much cheaper in #30 cylinders, but not many folks want to spend $300 for one
to get $10/lb R-12.

On Tue, 29 May 2007 12:08:53 -0400, Tom Adkins >
wrote:

> I will take exception with you about "topping off" an R-12 system though. If the
>system has a leak, it really doesn't make financial sense unless you have a supply on
>hand and are doing it yourself. Shops are charging $25-40/lb in my area, and the 1lb
>cans still generally sell for that price. It seems like a waste.
> R-12 is much cheaper in #30 cylinders, but not many folks want to spend $300 for one
>to get $10/lb R-12.

Now you're talking a range where it starts to get spooky. One of my
biggest fears has been hearing an overall repair bill of $300 PLUS (I
emphasize the plus because I imagine it can climb significantly and
quickly above that mark). Another writer mentioned it only being fair
to pay the service tech's time for troubleshooting the system although
many shops WILL convert (or include) that time toward the repair bill
if repairs are done with them. That too is fair enough though, a
worst case example might be for the troubleshooting time=$100 and
repairs+~$500

I'm a little concerned about this for a couple of reasons, one; I
remember years ago as a teenager working in a service station that the
'gravy' jobs and the ones that climbed into the hundreds of dollars
THEN were air conditioner related in the summer. two; the last time I
visited my GM dealer for a tune up and fuel pump, they shocked the
bejayzus out of me when they presented me with an $850 bill that
included their 'troubleshooting' time added on with spark plugs at
$10ea.

Interestingly enough, over the weekend I found a parts site on the net
that offers dummy pulleys for when ACs fail and costly repairs are
hoping to be avoided - they've probably been around but I didn't
remember seeing those. So... I'm cool with paying a moderate amount
towards a repair bill but I think these days too, repair bills cn
quickly cross any lines of 'reason' and turn into hard lessons learned
if one's not careful with their approach.. ;-) Hence, my visit
here. Usenet's a great place...

cover wrote:

>
> Now you're talking a range where it starts to get spooky. One of my
> biggest fears has been hearing an overall repair bill of $300 PLUS (I
> emphasize the plus because I imagine it can climb significantly and
> quickly above that mark). Another writer mentioned it only being fair
> to pay the service tech's time for troubleshooting the system although
> many shops WILL convert (or include) that time toward the repair bill
> if repairs are done with them. That too is fair enough though, a
> worst case example might be for the troubleshooting time=$100 and
> repairs+~$500
>
> I'm a little concerned about this for a couple of reasons, one; I
> remember years ago as a teenager working in a service station that the
> 'gravy' jobs and the ones that climbed into the hundreds of dollars
> THEN were air conditioner related in the summer. two; the last time I
> visited my GM dealer for a tune up and fuel pump, they shocked the
> bejayzus out of me when they presented me with an $850 bill that
> included their 'troubleshooting' time added on with spark plugs at
> $10ea.
>
> Interestingly enough, over the weekend I found a parts site on the net
> that offers dummy pulleys for when ACs fail and costly repairs are
> hoping to be avoided - they've probably been around but I didn't
> remember seeing those. So... I'm cool with paying a moderate amount
> towards a repair bill but I think these days too, repair bills cn
> quickly cross any lines of 'reason' and turn into hard lessons learned
> if one's not careful with their approach.. ;-) Hence, my visit
> here. Usenet's a great place...

It's not uncommon for an AC repair to easily reach $300. I've done a few already
this season that were close to $1K due to crashed compressors. The compressor alone is
often $2-300 before installation. On a Mitsu Spyder I did recently, the compressor
alone was $450. Aside from a leak at a fitting, AC repair is seldom cheap, and if done
on the cheap it often leads to more costly repairs. On your 17 year old T-Bird, a $500
repair bill for the AC isn't out of the question.
If you don't fix your AC and the pulley bearing on your compressor is good, the
bypass pulley isn't needed. The compressor will just be along for the ride. They are a
good option if the pulley bearing has failed.

"cover" > wrote in message
...
> On Tue, 29 May 2007 12:08:53 -0400, Tom Adkins >
> wrote:
>
> > I will take exception with you about "topping off" an R-12 system
though. If the
> >system has a leak, it really doesn't make financial sense unless you have
a supply on
> >hand and are doing it yourself. Shops are charging $25-40/lb in my area,
and the 1lb
> >cans still generally sell for that price. It seems like a waste.
> > R-12 is much cheaper in #30 cylinders, but not many folks want to spend
$300 for one
> >to get $10/lb R-12.
>
> Now you're talking a range where it starts to get spooky. One of my
> biggest fears has been hearing an overall repair bill of $300 PLUS (I

Phhhttt. $300? That's pocket change for A/C work.

If you are reasonably mechanically minded you can do your own A/C work
if your willing to invest maybe $300 in tools, and some time in reading the
documentation and understanding it. R12 systems fall into 2 categories:
those that use old-style compressors that have an oil resivor (York, etc.)
which are worth repairing with R12 (meaning, they will stay fixed) and those
that use newer compressor designs, those are absolutely not worth touching
with R12 because those compressors are generally all **** and will blow up
2-3 seasons later. Any R12 work requires an EPA certification in order to
be able to buy the R12, which costs
time and money (not a lot of it) to get, it's not difficult material to
understand,
though. There's tons of old 10-20 year old R12 cans on Ebay cheap. People
hoarded it figuring years later they would make a killing, but
underestimated the
speed at which R134 would come in, they also didn't forsee the government
mandating reclamation which has put a lot of reclaimed R12 on the market.

You can retrofit a R12 system to R134, it's not hard, but it won't cool well
unless you replace the condensor with a much larger and more efficient one.
If you have space in the body of the vehicle it might be worth doing.

Minimum tooling you need is an electronic leak detector, a vacuum pump,
a vacuum guage (which should be part of a manifold guage set) and the
various fittings to connect the freon cans. If your working on a
charged system you can drive the car to a shop and they can evac the
system cheaply. That will help you to be ecology friendly. Years ago
we routinely dumped R12 to atmosphere, I wouldn't do that today. As
for dumping R134, that's a touchy subject. Legally you must recover it -
but what the EPA fails to mention is that all medical asthma inhalers use
R134 as the propellant, and there is no restrictions on those, and R134
is used to form bubbles in foam insulation manufacture which dumps
millions of tons of it to atmosphere every year, it's the single largest
source of R134 vents to the atmosphere. R134 was also selected for
it's environmental friendliness, so you might consider the recovery
laws on R134 somewhat hypocritical. What I have done is to find
a quick-lube place that does R134 charging, tell them there's a crack
in an AC line that is leaking and I went and bought a replacement line
but just need the system evaced so I can replace it. Lots of times they
will evac the system for free, thinking I will come back with the fixed
system, of course, once I get the system drawn down I just never come
back and I charge it myself. Considering they get money from the
refiners for the recovered refrigerant, it's a fair trade. Do this kind
of thing on a slow day, of course.

>
> I'm a little concerned about this for a couple of reasons, one; I
> remember years ago as a teenager working in a service station that the
> 'gravy' jobs and the ones that climbed into the hundreds of dollars
> THEN were air conditioner related in the summer. two; the last time I
> visited my GM dealer for a tune up and fuel pump, they shocked the
> bejayzus out of me when they presented me with an $850 bill that
> included their 'troubleshooting' time added on with spark plugs at
> $10ea.
>
> Interestingly enough, over the weekend I found a parts site on the net
> that offers dummy pulleys for when ACs fail and costly repairs are
> hoping to be avoided - they've probably been around but I didn't
> remember seeing those. So... I'm cool with paying a moderate amount
> towards a repair bill but I think these days too, repair bills cn
> quickly cross any lines of 'reason' and turn into hard lessons learned
> if one's not careful with their approach.. ;-) Hence, my visit
> here. Usenet's a great place...

AC work is just tedious, it takes a long time to do it right. That is why
it's
so expensive. It is really one of those areas where the savings to do it
yourself are so large that it is worth doing yourself. Unlike, say, oil
changes.
With oil changes I have it down to a science I've done them so many
times, but still, with oil at $1.50 a quart and the filter at $5, and my
vehicles
use 5-6 quarts, for me to do the change saves $6 over going to the corner
change place when they are having a sale - it's hardly worth DIY it anymore.

Ted