Had an issue today. Found that the AC system in my recently purchased 69 442 was improperly serviced with R 134 Freon. 400.00 bucks later system has been purged and re serviced with R 12. Shop owner told me that the POA valve needs work. Pressure is excessively high a 43 psi. My question is can anyone direct me to instructions on rebuilding the POA valve. I'm gonna wait till cooler weather to do this, but I would like to source parts and instructions in the mean time.
Will also replace the dryer at the same time.
Any help and/or instructions will be greatly appreciated.

 

Need to know high side pressure and ambient temperature to determine if that is actually "excessively high".

 

OAT=95
Don't know High press
Freon added after purge= 4 lb
1 hr vacc down to -29 hg
Now cool temp at center vent 40*

 

I may be wrong, but don't you need a lot more than a vacuum job to go from R134 to R12?
Like a full flush, and replacement of the desiccant, at least?

This sounds like a job that needs a full teardown to me.

And I don't think you can rebuild a POA valve without specialized equipment.
There are folks who do, who will rebuild yours or take it as a core.

- Eric

 

if you need that poa valve checked out/ rebuilt, I can do it.

 

Well that is a very critical piece of information and I don't see how there is any way of knowing if the system is operating within nominal parameters without that information. Your shop didn't check the pressure when they charged the system? Heck, I'm just an average Joe and I have a set of gauges and check the pressures any time I work on the AC. It's like trying to adjust the distributor advance without a timing light.

 

Kenneth,
I'm sure the shop checked the high pressure but I was not present during final service and I just did not think to ask what the pressure reading was. I have very little knowledge regarding the required AC pressures. Maybe I can call the shop today and ask the owner what that pressure was. The shop was excellent and the owner was the man that did the work as his employees were all more familiar with later model vehicles.
Thanks for the reply and I'll try to get the info needed

 

Kenneth,
I just spoke with the AC shop and the owner told me the high pressure reading was 225. He will be sending me an invoice with all findings and readings.
I was present at bill pay time when his computer locked up on my receipt and I ask him to send me the specifics when his computer was back to operation.His hand written receipt does not give specifics
Thanks for your help. Looking forward to your thoughts on this.
Jerry

 

I checked my 1971 CSM and it said a full charge is 4 pounds, so it appears the system is charged properly.

 

Yea I hope all is good. I took my CSM with to the shop and ask if he would like to review it, which he did.
Thanks again for your reply
Jerry

 

Eric, I hope that the removal of the R 134 and a good vacuum will at least get me thru the summer here in Tucson, Az. Then if I can get my sh*t together then I may remove the entire system to re seal and repair all.

Banny, Too bad I didn't know what needed to be done prior to shipping my 442 from Dallas. Maybe if the PO had known about the mis-service with R 134 he could have visited you for repairs. Oh well. To late now. My car was picked up from Texas Motor Speedway 2 weeks ago tomorrow.
Just my story "a day late and a dollar short"
Jerry