Yet another air conditioning thread!

[Ringting]

Excellent Knowledge! Much appreciated.

Wise person that Marquis de Sade.

[Piece-it pete]

Thanks guys! Auto Zone shows it fitting 83 and 85 CVs and GMs, but says it doesn't fit my 85 TC, very strange and probably wrong. I'll compare the pic to my hose here at lunch and report back.

Pete

[1987cp]

iirc, the clutch diode is across the connector at the compressor clutch. I have recently had my 86 apart but it doesn't have C461, so no help there. There is a ton of R-12 on ebay and craigslist, to be legal you need an EPA 609 certification, or state to the seller that you are buying the R-12 to resell to a certified technician. I took an on line course for $20 and got the licence. I am rebuilding the a/c on a 68 Cadillac Fleetwood (takes 4 pounds of R-12)! Prices on ebay are all over the place, if you are patient you can pick it up for around $25 per 12 ounce can, shipped.

That sounds a lot more expensive than buying R134a by the can! Is there any reason at all to continue using R12 in an older system if you can obtain seals that are R134 compatible?

[Lincolnmania]

some of the old compressors will not work with r134a......for example, late 80's caddys spit out compressors if you try to use 134a

[1987cp]

Does that have to do with having butyl instead of Viton internal seals?

[Piece-it pete]

Installed the discharge hose, accumulator, o rings, orafice tube....

The discharge hose from Auto Zone does fit, but I had to bend the pipe that attached to the condenser to clear the battery.

As long as you take care to not break the metal pipes from the condenser and evaporator, I think it's a great backyard mechanic job, much simpler than I thought.

Thanks for the help!

Pete

[gadget73]

Does that have to do with having butyl instead of Viton internal seals?

more to do with the pressures involved R134 runs higher than R12 does. R12 also cools better.

[Lincolnmania]

i just did skippys car........i didnt change a thing, i added r134a fittings, vacuumed it down, added four ounces of ester oil and charged it up with 2.5 lbs of r134a........100 degree ambient temp, 43 deg vent temp.

[1987cp]

Something I've surely wondered aloud about this before ... what are these "R134 fittings" you speak of? I assume they're readily available ... is this the sort of thing you speak of? And does it really cost 11 bucks?

http://www.ctd4ac.com/actools/221359.asp

[gadget73]

They actually look like this, blue on the left is the low side fitting, red on the right is the high side.



They have a female thread inside that screws over the original R12 charge ports. The better ones require that you remove the shraeder valve from the original r12 fitting, and the valve inside the new 134 fitting takes care of business. The cheaper ones basically have a long pin inside them, and it just pushes down on the valve inside the R12 fitting. Those tend to leak if the pin bends or sticks at all. A pair of fittings is probably 10-15 bucks. The whole reason for the fittings is some mandate that says each refrigerant must have unique service port designs, basically so you can't accidentally put the wrong juice in. Think of it like compressed gas cylinders, they're all different and for the same reason.

[Lincolnmania]

the cheap ones suck, had a low side fitting that i could see thru, didnt notice this until i pulled the hoses off and i could feel it sucking vacuum

[1987cp]

Well, I'm shocked. I got one of the $45 retrofit kits at AutoZone and a can of R134-plus-dye. The compressor wouldn't run at first, so I jumpered the low-pressure shutoff to get it to suck refrigerant into the system. I put in the can of dyed R134 plus one can from the kit, and it's running with the low-pressure switch plugged in and blowing cool. Thinking I may want to add another can, since it's pretty certain the former refrigerant level was quite low.

The downside is that the fittings are the cheap type, but I don't think I'm going to worry about that unless I notice one leaking.

[gadget73]

Cheap ones usually work initially, but they don't hold up if you have to charge it multiple times. I had one explode on the Mark VII when I decided I wanted to hook the gauges up just to see what it was doing. It was leak free, but when I pulled the gauge off it didn't seal up again, and just spewed refrigerant and oil all over the place.

[torquelover]

Do you still have the huge hole in the HVAC plenum?

[1987cp]

Cheap ones usually work initially, but they don't hold up if you have to charge it multiple times. I had one explode on the Mark VII when I decided I wanted to hook the gauges up just to see what it was doing. It was leak free, but when I pulled the gauge off it didn't seal up again, and just spewed refrigerant and oil all over the place.

Eek. I guess I'll hope for now I don't have to charge it again!

That must be the origin of the reference for the plunger on the fill port sticking up and being stupid.

One question, what the heck is the other port for if the rear one is where you fill it? Just for system diagnostics to see if you have a weak compressor or something?

Do you still have the huge hole in the HVAC plenum?

You mean from when you tried to catch the car on fire? Yeah, that's still there. Suspect I'll get better performance in both heating and cooling without it. I've got some aluminum HVAC tape that should be sufficient to seal it up a bit, just got to get around to getting under there and putting some on.