Oriscany421

Well they don't make it anymore and if you can find it it is $800.00 for a 30 lb cylinder to start with.

Shark2626

You just replied to a thread that last ended in 2014? Anyway...

A lot of entrepreneurs bought up the supply of R12 when it was announced that it would be discontinued, and they are slowly selling off their inventories at a nice profit.

You only need 4, maybe 5 cans maximum, if your system is completely empty.

Look on Craigslist and eBay, should be about $20-$25 a can. I bought mine off of Craigslist and lucked out, the seller delivered them to me for free that same day.

928NOOBIE

I've converted and other than having to top it off every now and then ...as in maybe once a year since I haven't had the hoses relined or bought new ones it blows plenty cold...I adjusted the freeze switch probe and I've measured 18 degrees coming out of the vents....it'll of course freeze up but the point is the potential is there....the shop that did it has done others and tells me the 928 takes the conversion well. Mine certainly has. now if I can quiet down the "doors" on the heater and quit them from rattling I'd be a happy camper...they make lovely squeaking noises when I adjust the temp with the heat on....so I know they are working lol....I'm going to see if I can reach them with maybe some odorless white lithium,or something a little similar.....

The Forgotten On

The hinges are fairly easy to get to. You can get to one side (and adjust them at the same time) by removing the glove box.

The opposite side is easier to get to but harder to see as you need to remove the rubber cover near the gas pedal and aim up under the dash.

928NOOBIE

Awesome Blake thanks!

Update: Got some "dry graphite" spray and used the straw to spray upward a very small bit above the motor that runs when you adjust the temperature and squeaks are gone. No residual odor. Job done.

dr bob

My car is also converted, almost 25 years ago now. Now that it has a hibernation season, it gets a little refrigerant to make up for losses through the compressor seal. Our climate here is really dry, as it was at our previous home near Los Angeles. The freeze switch is bypassed, so the car presents center vent temperatures in the 17-19º range while cruising. Freezes fingers on the steering wheel.

Meanwhile, the temperature setting motor is what seems to make the most noise, a bit of gear noise as it adjusts the doors and makes/breaks switch contacts for the rest of the system. I leave the slider at 70º most of the time, and let the system do what it does best as far as managing cabin temperature. In the quiet cabin, the noise is noticeable as the servo 'bumps' the door positions to maintain the target temperature. At some point it will bother me enough to do some remedial cleaning and lubrication. The door pivots make no noise, as their actual movement is pretty slow.

928NOOBIE

Hey Dr Bob

Do you have any issues with the evaporator freezing up since you've bypassed the freeze switch? Do you shut the compressor off manually using the button?

My motor also makes gear noises but this morning something was squeaking again ; I can only really hear it if I"m stationary and the radio off....its a little better since I used the dry graphite but could still use some help.

dr bob

On seriously (hours) extended drives while in Cali I had a couple freeze-up episodes, solved easily by turning the AC off for a bit. Stopping for something every few hours also gave things a chance to thaw and drain.

But we live on the desert side of the Cascades now, several thousand feet altitude, so not enough humidity to make it an issue. Summer touring here is at altitude and often as not is a no-AC experience. If I plan an extended ride with AC on I can always take the few minutes to un-jumper the switch. From our previous home above Los Angeles, and much more driving duty, the sub-freezing vent temps helped cool the black car a lot faster. The two seasons there are summer and not-quite-summer. AC had duty for all but those few weeks of not-quite-summer when daytime highs were only into the 50'sF. I generally kept the heater valve tied closed all year with a zip tie. Sometimes it would get clipped, but only if it got seriously cold, like the 40'sF. Brrrr!

For folks in non-desert climates, jumpering the freeze switch won't buy you more cooling. A larger fraction of the AC cooling capacity is spent condensing the humidity from the conditioned air, leaving less capacity to cool once the moisture drops out. The good news is that the humidity reduction makes it still feel cool in the cabin, even though the thermometer may not read that low. But that condensing moisture will tend to freeze on the evaporator tubes at points out of direct airflow, and particularly at the area just at the inlet from the expansion valve. Once ice starts to even partially block airflow in that area, more ice forms until the whole evaporator is a block. So while your vent temps may be well above freezing, you can still manage to make ice in there that will eventually choke off airflow, and on the way reduce the total cooling available for the cabin. The compromise for all this would an option like a time-delay relay that would bypass the switch for the first maybe 15 minutes or so of AC use, then go to normal operation after that. You'd have the possibility of faster initial cabin cooling, and still avoid the risks of freezing the evaporator.

Some work with one of these would do the trick. You can mount it right by the freeze switch so no wires to stretch. With a dual 5-pin relay socket setup and power lead you could combine the freeze switch bypass duty with the clutch relay duty, see This relay has 10A contacts rating. Without digging in to wiring specs and such, I'd be adding a standard 53b with this to do the actual clutch switching duty.

928NOOBIE

Thanks for the good info Dr. Bob. I put an "ice cube" relay in the engine compartment so we have the load based circuit from the climate control module through the defrost, freeze switch and pressure switch into a trigger only....should help extend the life of everything between the Compressor and the climate control module. I'm going to play with my freeze switch probe once the weather changes. Particularly on warm humid days on lower fan settings it can freeze up here in Kansas City....we can get pretty high humidity in hundred degree weather....

dr bob

High relative humidity in high temperatures equals a LOT of moisture mass to pull out of the volume of air passing into the car.


On the freeze switch itself, remember that it's a consumable part. There's a hollow copper tip and a tube that nestles into the evaporator fins/tubes. The other end of the tube connects to a little bellows that expands and contracts as the fluid in the tip and tube grows with heat added. The bellows has a little micro-switch that opens and closes the compressor circuit. The fun is that the little bellows work-hardens from the constant movement from temperature change. Doesn't matter if the AC is running or not, except that the cold tip forces a motion cycle in the bellows. The range of motion at the little bellows diminishes with more cycles, to the point where the micro-switch no longer sees movement.

Were I designing that system today, there would be a low-pressure switch on the suction line coming out of the evaporator, maybe in the hard plumbing from the expansion valve to the fuel cooler. On low-side pressure below maybe 25 PSIG (about 30º gas temp inside....), the circuit to the clutch would open just the same way the freeze switch is supposed to do now. Add two schraeder charge ports there, one for low-side charging and the other for the suction-side switch. Then dump the freeze switch completely.