Old Chrysler A/C

[grumpy old man]

Just re-read my last rant and a huge apology is in order.

First it was not directed at anyone on this forum. Sometime around the 17th I went to bed feeling lousy and the next morning woke up with a temp of 102+ had that for 3 days and for obvious reasons no one would come near me. Dr finally sent me for corona testing and I had to stay confined until the test results came in. long story short having nothing else to do I curled up with my laptop and started researching the R12 R134 issue, R12 replacement R134 conversion etc...... Somewhere along the line my brain exploded and that rant was the result.

Back to the Chrysler. I did break down every connection and replace all the 55 year old o rings. While it was all apart I blew compressed air through the condenser and evaporator, got a ton of really nasty looking oil out of both. Sucked the oil out of the compressor and it came out all dark and foamy, looked sort of like a bad experiment with a German dark beer. I figured that what oil residue was left was probably inconsequential. Put 8oz of Pag 46 in the compressor.

Put the vacuum pump on for an hour and change pulled close to 30" and it held all night. Next morning put it under can pressure, no leaks that I could find so started it up and turned on the A/C. No power to the clutch. Jumpered the clutch and charged the system, works great. This thing will freeze the gonads off of a brass monkey. Tried to trace the clutch circuit but without a wiring diagram I would need to cut into all the looms to trace the wire and would rather not get that crude. Is there somewhere I can find a clutch circuit wiring diagram for this thing so maybe I can figure out what is wrong?

[Dougflas]

You're asking me to remember a 50 yr old system? If I remember, going backwards from the compressor there is a temp control switch probably controlled by vacuum. Sorry, this is too old for my mind.

[grumpy old man]

A friend of a friend managed to come up with a wiring diagram for a 66 Dodge. It was close enough that I managed to find the wire on the firewall side of the bulkhead plug. Once found it was relatively easy to trace and fix. The diagram shows the clutch wire going directly from the control to the clutch.

So it appears that the clutch circuit has no cycling system, apparently there is some kind of system to regulate evaporator temperature/pressure to prevent freeze up. The temperature control cable only operates the heater control valve. For whatever it may be worth to anyone who may look at this in the future for pertinent information it looks like the heater core controls the outlet temperature as the heater valve has a bourdon? tube that goes into the housing. Don't know for sure because the heater is bypassed. Looking under the dash I have no intentions of trying to replace the heater core, my 75 year old frame is no longer that flexible.

Now I just have to wait for a couple of months to see if it holds the refrigerant.

Thanks very much to all this one was a PITA. Having been fixing a lot of little things on this beast I am remembering why I could not wait to get out of the business back in the late 70's

Thanks again.

[grumpy old man]

However the EPR works I am impressed. This thing is spitting out air temp in the 30's with ambient temps in the 80's Don't know what it will do when we hit triple digits but what I remember about the average system of the time this one seems to be among the best.

Probably a mute point now as it is working and I do not believe I will be working on another one any time soon if ever.