On my 1990 toyota pickup the high side valve for the A/C does not fit my R-12 gauges. Does anyone know the size so I can buy a converter?

The system is virgin R-12, I bought the truck new and it has never been connverted.

Thanks,

-Glen

 

All R-12 hoses with R-12 fittings will fit the R-12 ports on the A/C compressor. Both the high & low sides are 1/4" threaded fittings.

My guess is you don't have the right hoses. You have the right gauge but not the right hoses.



Somebody correct me if I'm wrong & I'll adjust my statement.

 

Doubt you'll find a converter- different gauges for each type of refrigerant.

Are you mistakenly trying to connect the low side gauge to the high side, or vice-versa?

 

Are there more fittings under the hood?

the first pic are the toyota fittings, shiny is high pressure. Gauge fitting screws in fine on the low side.




This is the location where the fittings are, on the firewall passenger side. On the other side of firewall is evaporator.




These are the gauge connectors;



These are the caps. Big one is low side small is high side.

 

Yeah. There's a fitting on the compressor, next to the engine: the high side.

 

Actually... the high side might be...

the one on the left.

 

hmm....interesting.

You might have the 1/2" size on the high-side. I knew that GM had an odd-ball (larger size) on their vehicles but i did not know Toyota was doing the same at that time.

Well that being the case, by looking over at CPS website they have a 1/2" ACME charging hose.

http://www.cpsproducts.com/#/w-Hoses...tive-Acme.swf/


And then over in their "Brass Fittings" section they have a 1/2" to 1/4" if you only want an adapter to use your current hose on the high-side.

http://www.cpsproducts.com/#/p-adapt...dapters-ad84c/

Here's the link for all their adapters:

http://www.cpsproducts.com/#/w-Brass...utomotive.swf/



Now I have no idea what fitting yours is, I'm just giving you links to get you going. You will have to figure out what one you specifically have.

 

The rubber hose from the firewall to the compressor is the low-side. The refrigerant at that point has been converted from the high pressure liquid to a low pressure gas. Actually I should not say "up to that point". Where it converts is in the expansion valve/evaporator.

 

Low side is the rubber line high side is all hard line (aluminum) You can see the rubber right after the low side valve in your picture. They are different fittings so you don't charge the high side on accident. You don't need a to connect to the high side to work on the system ie recharge/vacuum out. The high side is just to diagnose if your compressor is building up pressure. Yes for you critics, it will pump down faster if you have both valves open, but it still works through the low side just fine.

 

Thanks for the fittings link.

I would like to see how the compressor is doing, thus gauge on high side. Any idea of the next smaller size from the standard gauge fitting? ...could it be a metric fitting? If I can find a nut to thread on, would that tell me size?

Someone must have a setup like this on here.

The evaporator was clogged with crap so I removed it to clean. I vacuumed and recharged through the low side and it works fine with much stronger air flow. That thing was 'crudded' out with Leaves, pine needles, dog fur, lint, mold, bugs.