Long story but my '75 GT sat with no engine for a couple of years. I assume the A/C was left open during that time period. Now back to together and running well, I started on the A/C yesterday. I evacuated the system with my good vacuum pump and the system did maintain the vacuum for at least an hour - a good sign. I then began filling the system with EnviroSafe as I have done in the past. From past experience, the A/C works well with around 20 psi low side pressure and 100+ psi on the high side depending on the outside temperature. Unfortunately the low side pressure goes to a vacuum regardless. The high side pressure only increases with more refrigerant. I'm guessing the dryer is plugged it having been left open for years. Anyone have experience with this?
Definitely change out the drier if there is even a remote chance of the system being left open for more than just a brief period of time, especially if using R12(liquid gold). If the system was left open, installing a new expansion valve would probably be a good idea as well.
Went out today to replace the dryer and expansion valve but found the A/C system totally empty. Not a good sign. I doubt the o-rings were replaced when installed again with the engine. These are the original A/C hoses now near 50 years old. I understand they now make a better "barrier" hose. Anyone know someone reliable who can rebuild my A/C hoses? I'm willing to ship mine out for the service.
Thanks andrewok1. I had just found that place. Will give them a call. I still want R-12 ports in the fittings if possible. Otherwise the system ends up with mixed R-12 and R-134A ports. This '75 GT also has an in-line refrigerant reservoir (big can) with, I think, brazed fittings. Not sure why the system has this but assume for good reason.
Since the system has been opened up and/or inoperable for a while, I'd also check the POA valve for correct operation as well, these are getting kinda pricey if you need to replace it. It's a simple procedure. The original Ford/Delco style aren't rebuildable, but the Frigidaire versions are. FWIW, When I replaced my a/c hoses I was able to find a local a/c shop to switch over to new barrier hose but re-used the original metal hose ends/fittings, maybe that could be an option for you. Hope this helps
That should be POS not POA! I replaced that worthless suction throttle valve years ago with an Old Air Products POA update kit. The Old Air Products POA is essentially a straight pipe with a sensor to shut off the compressor if freeze up is imminent. Also Cold Hose says they can reuse my A/C hose fittings.
Don't know why but Cold Hose says this must be a muffler since the system has an expansion valve. I still bet it's a suction line accumulator to prevent oil and liquid refrigerant from entering the compressor. Either way Cold Hose says they can handle this when building new hose lines. Reminds me too I was always told to refill refrigerant through the low pressure port in the POA far upstream of the compressor to insure that liquid refrigerant changes phase to gas before entering the compressor.
CLARK ITS ANDY ,WITH 134A YOU dont need that said muffler ,you have accumalator at condensor /ANDREWOK1
CLARK COLD HOSE PEOPLE HAVE BEENAROUND 50 YEARS OR BETTER THATS WHERE I GET ALL MY AC STUFF /ANDREWOK1
TODD ANDY HERE I HAVE ABOUT 8 OF THE POA VALVES FACTORY R22 NEED ADJUSTED FIR PROPER OPERATION r22 is 28 lbs and 134a is 26 lbs critical
Must just be a coincidence that Dennis is now talking/typing in a loud voice, just like Andy does at times.....
Yep, I have a few NOS POA valves collecting dust as well. Andy, I remember you speaking about the issues you experienced when you had the "updated POA" valve kit, better a/c performance was realized once you reinstalled a good working POA.
No Lomger... Andy just made Like Willie Nelson, he`s "On the Road Again"... We had a good time fooling y`all
I pulled all the A/C hoses out of the '75 GT early today (before it got so blamed hot)! One big joint was only finger tight and the O-ring was all chewed up at the low pressure side of the compressor. A wonder the system held any vacuum at all. Certainly why it bled out my refrigerant fill. This is what I get when engine installation is done with me 2,000 miles away. I did see that to replace the A/C dryer I'm going to have to pull the radiator and the condenser. Sheezery.
Finally got in the rebuilt A/C hoses from ColdHose.com for my '75 Ranchero. All looking very nice and work done as I requested. I removed the radiator and A/C condenser Saturday - a cooler 85F day. All had to come out to replace the dryer. Sunday, back in the 90's, I reassembled all with new o-rings. Got all finished. Hooked up my A/C vacuum pump and vacuum gauge AND sheeez! Such a vacuum leak I didn't think the gauge needle would even move! Oh well. I'll wait for another cooler Colorado day to attack this again. The hoses were all rebuilt using my original end fittings save for the condenser outlet on the lower right side of the condenser. That hose end itting was badly corroded. I'm thinking today that the nose maybe too long on that replacement fitting and not allowing the o-ring to seat.
