I'm going to have to assume a couple of things..... the pressures you are
reading are low side pressures?? and that the old compressor was replaced
with no other work (other than the recharge) to the system??

When a compressor fails internally there's all kinds of little bits and
pieces that used to be compressor that infiltrate the rest of the system. I
think that you'll find (at the very least) that the orofice tube and
condenser are both plugged off. If you are real lucky, none of this crap has
made it around to your new compressor (the viscious circle starts here).

I'm not sure who is training folks to avoid servicing the rest of the system
when replacing a pooched compressor but I think you are seeing the validity
of "cutting costs" in this manner.  When I replace a compressor because of
an internal failure, the car gets a new condenser, orofice tube and
receiver/drier...... there is no way on Gods green earth that I am about to
risk giving away free parts and labour because I didn't do what should have
been done. Additionally, the evaporater core is back flushed as are all the
hoses (though I have changed hoses with mufflers in them). If all of the old
stuff isn't spotless clean inside, we are only rolling the dice to see how
long before we repeat the process.......

We need to remember that these compressors aren't compressing liquid, they
are compressing a gas and, as such, their internal tolerances are really
very fine. It doesn't take much wear to have a system that just doesn't
perform well enough to keep most customers happy. Like I keep saying, I'm
spendy.... very spendy - but after the sticker-shock wears off, my customers
are happy.

Back to your problem.... if I were presented with your car in it's current
state, I would replace the "usual" parts and, quite likely, the
compressor.... in my mind, it is now suspect and I would have some real
concerns about offering any kind of warranty (or even releasing the car)
with what amounts to a ticking time bomb under the hood.

If you will be performing the work yourself, I'd suggest replacing the
"usual" parts and flushing the remainder of the system very, very well.
Ensure that the correct amount of oil is added and evac/recharge.

I realize that this is an old car and that pouring this much money into it
may not be financially feasable, but it makes less sense to waste money
through inadequate repairs.

HTH

I have to agree with Jim.
Your desire to save money does not make parts serviceable.

When I worked on AC, I often had customers tell me that, *because they
wanted to save money*, parts were OK, and didn't need to be replaced.
It just doesn't work that way.
When a compressor goes, it often grenades, spewing metal everywhere in
the system. That metal must be removed; if that means replacing parts,
that's part of the cost of having AC that works.

Bill Funk
Change "g" to "a"

Well, you're dealing with a pretty bitchy pump in this case.  Thanks Ford!

My experience was similar.  I believe what happens is the R12 oil vs the
R134A might create a flammible substance.  When my system did what
you're describing I found a LOT of crud in the system - enough to
totally clog the condensor ($$) and orface tube.  I found sludge, metal,
and plastic...

#1 - tear it all apart, clean every inch of it with LOTS of 92% rubbing
alcohol (any pharmacy will have it).  This includes the upper hose set.
 I'm still using my original factory upper hose set - its survived the
abuse of R12, R134A, and severe overpressurization.  Be careful not to
expose yourself to too much of this stuff, it will kick your a.s in a
not so happy way.

Once clean, you should find 'not much' back pressure on any given part...

#2 - I found my condensor was clogged up and would not unclog.
Apparently pump-bits found their way into there...  $150 later the
system worked nicely.

#3 - replace the orface tube.  This is at the coupling by the passenger
exhaust manifold between the flex hose and the condensor.  Removing the
airbox will get you pretty easy access.  They call for a tool to remove
the orface tube, personally I was able to get at it with some grippy
hemostats

#4 - replace the dryer.  Bloop there goes $30.

#5 - drain pump carefully, fill with R134A friendly oil, drain, refill,
etc...   until what comes out is clean.  I was too chicken to pour
alcohol into the pump IIRC (hey, its been a few years).

#6 - replace all o-rings with green ones (black O-rings don't like R134A
friendly oils) re-oil everything with PAG or whatever (the R134A
friendly stuff), and recharge.

#7 - engine overheating at idle with the A/C on.  Needed a fan clutch.

#8 - after all the drama my pressure switch was leaking (would kick the
compressor off when the system had plenty of pressure, I guess the
diaphragm had a hole popped in it).  I wanna say that cost me $8

Also ONLY REFILL THE SYSTEM WITH 70% OF ITS R12 CAPACITY.  Overfilling
R134A seems to cause some really odd things to occur.

Personally I didn't have access to a pump to pull the system down with,
so I went ahead and left in "one atmosphere" of moist texas summer
air...  I'm sure it didn't do the system any favors, but hey it works.

Officially my AC repair has outlasted two transmission overhauls.  on a
95F day it blows 37-40Fish at highway speed on panel air, next to the
top fan setting.  On a 90F or cooler day, it'll hang near freezing.

JS

John, not to sound belittling, but the reason the orifice tube and the
dryer are replaced is not to make the mechanic rich, but to get EVERY
last bit of contamination out of your A/C system. I'm having the dryer
and orifice tube replaced along with the leaking evaporator on my
Explorer. A $600 job, but the compressor alone for a Explorer can cost
that much. Before you do anything else, do the job right by flushing the
system, putting in a new orifice tube and dryer, and then recharging the
system. Anything else is false economy. Besides, it sounds like you are
doing the work yourself, the parts and refrigerant shouldn't cost more
than $150 max.

Good luck. I feel for you, this Florida sun is a bitch.