harveyf

I did a little searching. 1/4" valves seem to be readily available. But it strikes me that the ones on a 928 might be metric. Anyone know for sure?

Rob Edwards

All A/C fittings on a 928 are the same ACME thread fittings as on any 'American' car.

dr bob

Whenever I use something that says ACME on it, I stop and listen for the telltale whstle of a large falling rock. From my disturbed childhood I'm sure.

harveyf

Beep Beep!

dr bob

That happens only after the impact.

The Deputy

Be sure to install the caps on each fitting, high and low side, especially if you live in a cold weather climate. I believe, if my memory serves me right, R12 and R134a are both about -15 degrees F at 0 psig. So, if it gets below -15 degrees outside-temperature, the gas is actually warmer than the outside temp and it pulls the Schrader valve down...opening it so freon can escape. Or something like that, been a long, long time since I've taken any kind of A/C class. Anyhow, if you look up inside the caps, you will see an o-ring...and that o-ring is there for a reason...and that is to keep freon from leaking out, if the Schrader valve is pulled down during the winter months.

A missing cap is the number one reason systems go empty here in Michigan over the winter.

It's funny reading about pressurizing the system, brings back fond memories. I worked with a guy once that pressurized the system with shop air...talk about adding moisture to the system...lol. He was a hack and l watched him ruin more air conditioning systems than l could shake a stick at...and this is why you should do your homework when pursuing an A/C tech.

Go to a shop that specializes in air conditioning, they will most like charge more...but your system will probably work much longer. Sure, I'm certified in A/C repair and feel comfortable charging my own stuff or a friends for free...but to do it for a customer...not so much.

Converted my 928's unit over to R134a last week and it blows cold.

Brian.

Kevin in Atlanta

Can a vacuum pump set up for residential HVAC be converted to 134a?

Rob Edwards

The pump is agnostic to what kind of system it's being hooked up to, any decent vacuum pump ought to be able to be plumbed with r134a-compatible fittings. Is this what you're asking?

Kevin in Atlanta

I'd like to know where I can find 134a fittings for a Robinair vacuum pump.

Rob Edwards

Here:


If this doesn't screw directly onto the inlet of the vacuum pump, usually you can adapt it to the inlet of the pump with common fittings from H-D or Ace.

Eplebnista

I have a tank of CO2, but have no idea if it is dry.

I am going to be attempting to fix the AC on my sister's Acura over the holiday weekend. The compressor seal is leaking, so it will need to be evacuated and recharged after the compressor issue is addressed.

The CO2 in the tank was not purchased as "dry" when refilled. Should I use it?

Ducman82

CO2? what would you use THAT for?

Eplebnista

See Dr. Bob's posts #20 and #24. Use a "dry" pressurized gas to test for leaks as "holding vacuum" is not as good a leak test as a pressure test.

I also have an ASE study guide that mentions using dry nitrogen as part of leak testing/evacuation procedure.

dr bob

Your CO2 cylinder is fine for the duty. Industrial bottled gasses are fine. Nitrogen happens to be plentiful, cheap, and readily available. If you have compressed air with a dew point of -40F or less you could use that I suppose. Most folks find that nitrogen is easier to find. Any welding supply store will have the bottles and a regulator. You'll need an adapter fitting to connect a refrigerant hose to the car.