On my 1990 which line is the low pressure a/c. There is a red cap on a line that is tucked down along the side of the radiator, is that the low pressure? also has anyone converted thier old r12 to r134 and if so what parts are needed.

 

On my 90 and 91 the low pressure fitting is up near the firewall by the accumulator...........

 

So it is the one with the blue cap that comes off the accumulator, which is up by the firewall?

 

you got it......

 

Thanks a bunch

 

The low side and high side port have different size fittings so its pretty much impossible to mess them up.

But yes the one on the accumulator is the low side and the one by the condenser and radiator is the high side.

Another thing on my Aero which is R134a on the low side hose suction hose there is a high side fitting this is NOT a high side port however a high side hose will hook up there.

The only reason I see for having this fitting was in the factory the compressors didn't come shipped with oil. At least when I replaced mine last year (Ford Remanufactured) it didn't. So the since the fitting is on the suction line Ford vacuumed the system and injected the oil through that port it then went downhill into the suction side of the compressor.

If you intend to have it refilled at a shop when your done make sure they don't hook the high side fitting in the wrong place.

So we don't need to repeat outselves here is a nice thread about conversion.

https://www.ford-trucks.com/forums/6...sus-r134a.html

In that thread I also posted a link to another conversion thread and 96 gave some A/C informative links as well.

As for things to replace you'll need to replace the condenser, accumulator, get the proper 134a orifice tube or tubes if you have rear A/C. Flush the hoses and evaporator and compressor of all mineral oil. After that fill up with PAG 46 oil vacuum the system and recharge with R134.

Even after all this though be prepared for slightly reduced cooling.

If you want to charge yourself you will need a vacuum pump and a manifold gauge set. I got mine off e-bay a pump and a gauge set for 139 I believe. The only reason I did this was because I was sick of the unknowledgable "refill jockies" out there.

I pull vacuum for about 30 minutes with my 2.5 CFM pump. 15 is fine but I like to make sure any moisture has the time to boil off.

 

I found this great A/C related link its a conversion chart that cross-references the manufacturer A/C compressor oil part numbers to an oil type and viscosity.

For example I needed to overhaul my Accords A/C and just like Ford they had the common "Factory Part Number" ND Oil 8.

With this site you can cross-reference by compressor, vehicle model, or manufacurer part number.

It took me a few hours to find but it comes in real handy.

http://autoacrepairs.com/vehicle_manufacturer%20oil%20spec.htm

 

Thanks I'll check it out.