AMC A/C Rebuild tip

[Big Bad AMX]

Like so many of the AMXs, Javelins, Rebels and older AMC cars that received the optional factory air conditioning the system in my 1969 AMX was no longer functional or complete. The condenser, drier, compressor and compressor mounting brackets were missing and the original hoses were in poor condition. The ducting, interior pieces, evaporator and switches were in place though so about half of the system was there. The following is a summary of what was needed, what its basic function is and where I was able to find the parts to get my AMX's air conditioning fully operational once again.

The condenser mounts in front of the radiator and has the receiver (also called a drier) bolted on its left side (driver's side). This is the area in which heat dissipation occurs. As hot compressed gasses are introduced into the top of the condenser, they are cooled off. As the gas cools, it condenses and exits the bottom of the condenser as a high-pressure liquid. The condenser looks like a thin radiator. Had this been a part unique to the AMX I may have been in for a long, expensive search. Fortunately, other AMC models and years use the same size condenser. The condenser that is on my AMX came from a 1972 Ambassador Station Wagon. The mounting brackets needed to be modified but the condenser itself is the same physical size. 1969 and prior years might be a bolt in depending on the model. Take measurements to be certain and scavenge parts from sealed systems to avoid outside contaminants being in systems that have been left open. If you'd rather buy a new condenser JC Whitney does list them for AMC vehicles 1970-1988 at $144.95 each. Stock #78ZF2614TF. The JC Whitney catalog states their condenser "replaces original equipment, utilizes original mounting location and brackets - no alteration required". They don't list driers so you're on your own there for a new one. I was unable to locate any sources for new driers (doesn't mean they're not out there, just that I didn't find any).

As stated the drier / receiver bolts to the driver's side of the condenser. In the AMX it is in the shape of a long cylinder. The primary function of the receiver-drier is to separate gas and liquid. The secondary purpose is to remove moisture and filter out dirt. The receiver will need to be sent out for a rebuild if you want optimum cooling from your system. Mixing a new compressor with an old drier will also void the warranty on the compressor from some manufacturers. There are differences in the driers from model to model, some differences are very subtle and some are extreme. To prevent any headaches buy the condenser and drier together as one unit. And be careful when you remove the receiver from the condenser to have it rebuilt. The receiver is made of steel; the condenser is made from aluminum. After 25+ years these two metals will likely have bonded themselves together to some extent.

The hoses on my AMX were all there but were showing signs of age in cracking and dry rotting. The hoses vary from model to model so if you need hoses you should get them from the same model donor car. I took the hoses to a local shop that makes hydraulic lines for industrial and commercial equipment. They needed the old hoses for measurements to make the new ones. They also used the sight glass section of the old hose as well as some of the other metal sections of the old hoses that have unique bends in them. It is much easier to braze these old metal sections to the new hoses than to try to make
new ones. The brazed sections are not noticeable and when done correctly look very much like the originals. When finished the hoses were pressure checked. The cost to have all three hoses made was $110.00.

The AMC compressor is a York two-cylinder pump type driven by a belt. An electromagnetic clutch couples the compressor to the drive pulley. The drive pulley free wheels when the air conditioner is not in use. Since the compressor is basically a pump, it must have an intake side (a low-pressure side) and a discharge side (the high-pressure side). The intake, or suction side, draws in refrigerant gas from the outlet of the evaporator located inside the car. Once the refrigerant is drawn into the suction side, it is compressed and sent to the condenser where it can then transfer the heat that is absorbed from the inside of the vehicle.

The AMC compressor is mounted on the upper front passenger side of the engine. AMC used the same compressor and clutch for many years and on many different models. Compressors and clutches are still readily available from your local NAPA, Autozone, Checker, etc. Keep in mind that many of these stores sell compressors and clutches built / rebuilt by a company called Four Seasons. Not knowing York compressors were still available I bought a brand new Four Seasons compressor. Later, when attempting to evacuate the system for the first time, it was found that this brand new Four Seasons compressor had a major leak coming from its front seal. Not the kind of quality control I need. I later found where I could get a York compressor and purchased a new one (see below).

You will also want to buy new service valves. These mount on top of the compressor and are used for charging and discharging the system. The A/C hoses mount to these valves. There are two styles of valves for the York compressor; the "Tube-O" which uses a rubber o-ring to seal and a "Roto" which uses a Teflon seal. You must match the type of service valve to your compressor. They do not interchange so be sure you get the correct valves for your application. The A/C technician can explain how to tell the difference when you place your order.

The AMC aluminum mounting brackets for the York compressors interchange from 1966 and up V-8s. The compressor mounting brackets on my 1969 AMX 390 are from a 1971 304.

After collecting the pieces and parts I needed I started searching for a company that rebuilds automotive A/C driers. I asked local A/C shops, long time AMC hobbyists, other makes auto enthusiasts, and found nothing. I even came up empty searching the Internet. As a last hope I posted a message on the AMC World Clubs' website's Message Board and in a couple of days I had a few leads to follow up on. I settled on the following company that was recommended by a website visitor:

Classic Auto Air Manufacturing, Co.
2020 W. Kennedy Blvd.
Tampa, FL 33606
Ph. (813) 251-2356 or (813) 251-4994

Classic Auto Air Manufacturing sells York Compressors. Brand new they are $180.00 and come with a 12-month warranty. A rebuilt York Compressor is $160.00 and has a 6-month warranty. Price does not include the clutch (I had bought a clutch locally so you'll need to ask for their price). They do not require an exchange or charge a core charge. These guys will rebuild your A/C Drier for $58.00. (prices from 2003) They guarantee your satisfaction. I sent them my drier in mid-July and, at that time, they had a three-day turn around. Keep in mind installing a new or rebuilt compressor with an old drier will void the compressor warranty from Classic Auto Air Manufacturing.

After receiving the rebuilt drier it was time to begin reassembly (always be sure you keep the receiver capped or sealed. If left open the receiver will absorb airborne moisture and it will become saturated in only a matter of a few hours and be completely ineffective). The high-pressure hose was connected to the receiver and then installed on the condenser. Next stop was to take the condenser / drier assembly for a pressure / leak check. It was pressurized to 300 psi and yes, it leaked. The leak was repaired and it was ready to install in the car. Finding the leak before getting the system charged saved headaches and $$. It was a very well spent $60.00.

The last piece I needed was the top baffle seal that mounts to the radiator baffle. The baffle seal is basically a strip of rubber that mounts in front of the radiator with steel staples. I bought one from AMX Enterprises in Arvada, CO. I had a lower seal on hand that was in good shape so it was reused.

After all the pieces and parts were back in place it was time to have the system evacuated and charged. When you have it charged be sure they use dye in the process so it can accurately be checked for leaks. Leaks can be checked with a 'sniffer ', but the dye gives no false readings and no doubt about where a leak is. Basically they use a special light and glasses, which illuminate the dye to a purple neon. It makes a leak pretty tough to miss.

I made an appointment with the local MaxAir outlet and crossed my fingers that it'd all work correctly and cool to at least the 45-48 degree range. With fresh R12 in the system (it was designed for R12 so that's what I'm staying with) and a digital thermometer in one of the vents, the car was started and it began to cool. It exceeded my expectations as it eventually dropped to 29 degrees at an idle and built up a light coat of frost on the compressor and on the high-pressure hose.

I took it out on a 95-degree day and while driving at 55mph it was blowing a crisp 22.7 degrees at the vent. One week later (after about 150 miles of driving with the A/C on to circulate the dye) I took it back to MaxAir for the final leak check. It passed with no leaks and no problems.

With the brand new York compressor, a new clutch, two new service valves, a rebuilt dryer, a used condenser, three new hoses, and a new baffle seal along with the pressure check, charging the system and dye for a leak check the total was close to $800.00.

My AMXs air conditioning system now works extremely well. I am very happy with the final results. It was fairly expensive to get it operational and it did take time to hunt down sources for the needed pieces and parts. Trying to get an old A/C system working can really try your patience, but it was one of the last things my car needed and I wanted it fully functional. So why not get that old A/C running again? There's still time before summer hits and then you'll be glad you did!

[Thikstik]

Great info...I got my 75 Gremlins so cold , I call it the meat locker. And being a GM car guy, I like AM much better , as their AC cycles on /off to save gas.
I could add that a new o-ring at the expansion valve is good insurance. But removing nut can sometines tear out (twist) the evap line as it becomes rusted to it over time, and Its hard to get to being under dash. The vender you mentioned is actually able to sell a Sanden compressor with brackets. This unit uses less HP. Our old York compressors could cool a 2000 square ft house.--true really!

[ChevelleSSLS6]

this should be a "sticky"

[Thikstik]

Well, yet another reason to like AMC's. While at AMO show in Atlanta, I picked up a factory manuel. I was looking thru it while board and saw a diagram about the service valves. It showed that the ac compressor can be serviced without losing a charge. Simply back out the 3 position service valves and do whatever you need, like add oil, r/r compressor. Amazing.

[Big Bad AMX]

Thought I'd look up the parts on this and the condensers are still avaiable through JC Whitney, though like everything else the price has gone up. The part number has changed too.

SKU Number: 1JA P40462 Manufacturer Number: P40462
Manufactured by ACI A/C Condenser
Priced from: $225.74

Classic Auto Air is still around though they don't show AMC parts they rebuild all makes.

[expdchief]

Hi Does anyone know how to remove the factory A/C hose's that flow into the firewall of a 1970 AMX? It sorts looks like i'd have to pull virtually the entire dash out to replace them. Any help greatly appreciated. By the way, if anyone needs it done, Classic Auto Air in Tampa ( 813-251-2356 x 70232 Ask for Patrick) rebuild your original receiver/drier. Just had mine done $105 plus shipping. Nice job and retained the factory look. There are absolutely none available that I could find anywhere and I looked hard. Just an FYI. Thanks, Mike