Air Conditoning question

[Mrbill426]

For a factory air conditioned E-body ('72) that sometime during its lifetime was converted from R12 to R134 (RV2 compressor), besides the compressor electromagnetic clutch and the low pressure switch mounted to the dryer, are there any other required under-hood electrical components? 
I have seen adds for thermostat switches with a sensing tube to also be installed on the evaporator line.  I thought that was the job of the expansion valve which has a sensing tube too.  I read where the EPR valve should be removed from the RV2 compressor.  It was still inside the port so I did it when I rebuilt the compressor.

Is a thermostat switch required, or should I be good to go?

[MoparLeo]

Are you trying to use the original system because of its originality? The old system was not very efficient.
The upgraded Sanden compressor based systems are much better and more reliable.

[Mrbill426]

@MoparLeo, yes originality, or as close as I can reasonably come.  I am in the PACNW so won't be dependent on "cold" A/C all that much.

Are you trying to use the original system because of its originality? The old system was not very efficient.
The upgraded Sanden compressor based systems are much better and more reliable.

[Rich G.]

On the 73 I built I removed the EPR valve from the compressor and mounted a thermostatic switch on the firewall with the probe wrapped around the line going to the evaporator.  On my 71 I did the same thing but have a Sanden compressor in that.

[Mrbill426]

@Rich G. did you also retain the brass expansion valve that also has a probe on the evap line?  Or did your '73 have one in the first place?  I am not the original owner so am not sure what was there when new. 

On the 73 I built I removed the EPR valve from the compressor and mounted a thermostatic switch on the firewall with the probe wrapped around the line going to the evaporator.  On my 71 I did the same thing but have a Sanden compressor in that.

[Rich G.]

Yes, you still need the expansion valve.

[MoparLeo]

No electrical changes needed. If you are not really going to use it much, r134a compatible hoses, o-rings, compressor oil  ( POE for r134a), Proper refrigerant charge R-12 vs r134a. Add an ultraviolet dye when charging to detect future leaks.

[Mrbill426]

@MoparLeo  this is the switch I was referring to as an add-on "requirement".

No electrical changes needed. If you are not really going to use it much, r134a compatible hoses, o-rings, compressor oil  ( POE for r134a), Proper refrigerant charge R-12 vs r134a. Add an ultraviolet dye when charging to detect future leaks.

[MoparLeo]

Don't need it. Just run what it came with until you decide if you want to do a performance upgrade and not just appearance.

[Rich G.]

I believe that switch was use to cycle the compressor to prevent freeze up.

[Mrbill426]

Thanks for all the good information guys!
I still have to send my original hoses out for rebuilding as apparently they are not repopped.

[Rich G.]

Classic Air did my compressor hoses. They did a great job.

[Mrbill426]

@Rich G.  Yes I believe that is where I was planning to send them for rehab.  How is their turnaround time?  Not that it's going to heat up anytime soon around me.

Classic Air did my compressor hoses. They did a great job.

[Rich G.]

I don't remember but it wasn't that long. I know it wasn't cheap but then again what is with these cars!😩

[CudaA39]

quote author=Rich G. link=topic=27306.msg307649#msg307649 date=1673558320]
On the 73 I built I removed the EPR valve from the compressor and mounted a thermostatic switch on the firewall with the probe wrapped around the line going to the evaporator.  On my 71 I did the same thing but have a Sanden compressor in that.
[/quote]

Did you have any issues with it cycling too quickly/too late with this mount style?  I've read the probe had to be within the evaporator, but I wondered if just wrapping the feed tube would be ok.

@Rich G. did you also retain the brass expansion valve that also has a probe on the evap line?  Or did your '73 have one in the first place?  I am not the original owner so am not sure what was there when new. 

On the 73 I built I removed the EPR valve from the compressor and mounted a thermostatic switch on the firewall with the probe wrapped around the line going to the evaporator.  On my 71 I did the same thing but have a Sanden compressor in that.

I suspect you'd need to switch to a single a action expansion valve and not the dual action from the factory that had the threaded bung.