impalaman

1978 Vette, L-82 with 4-speed:

I want to use the R134 style fittings on my A/C system.

However, the schrader valve WILL NOT COME OUT OF THE LOW SIDE PORT. I cannot retrofit the low side port with a R134 style fitting because the schrader valve will not come out!

Were they designed to come out? I have the schrader valve tool, but when you unscrew the valve, it will get to the top of the hole and then will simply not come out any further. Is it designed this way?

Frustrated.

Ganey

Legally each freon is supposed to have installed the special fittings for it.

The valve should screw out, if not needle nose pliers should do it.
The valve may not need to be removed for the fittings.

427V8

I don't think you need to remove the old schrader valve. I think you just screw the new adapter one over the old one...

impalaman

After a little research.... the high quality r12 to r134a conversion fittings require you to remove the schrader valve from the existing low side port on the car.

The el-cheapo conversion adapters have a little plastic needle plunger so that when you screw it on, the schrader valve on the car is depressed.

Problem: The stupid bolt on the compressor is directly above the low side port. You can only get a 90 degree adapter on it. I bought a "Mastercool" 90 degree adapter but it requires me to remove the schrader valve. The el-cheapo is quite long and straight. Even if I were to put it on, I could not attached the charging hoses to it due to the compressor bolt being in the way.

If I could get the schrader valve out, life you be golden. I've tried the needle nose method. No dice. GM must have used kryptonite in it or something.

My last resort is drilling it out.

Anybody ever have a problem with removing the schrader valve on the low side port?

This car is all stock by the way. As you know, the low side port on the accumulator is in
a completely absurd place. I don't know why they bothered putting one on it. You can't get to it.

impalaman

That car must have heard me talking bad about it!

Just now went back to the garage and tried some alternative techniques to remove the valve. Used a very very small flat blade to pry upward on the tip of the valve while applying
rotational movement. Bingo!! It came out.

Call off the dogs guys. Thanks!!

markdtn

I would never use Freeze12. Do a search for posts on this. Even so, why change the fittings?

impalaman

Because the low side fitting is directly below the compressor mounting bolt. It's a pain to try and find angle tipped hoses to fit. I found a solid brass 90 degree r134 fitting made by FJC today. I installed it, and it works great. Also, the quick-connect pneumatic style r134 fittings are efficient and easy to use. They are superior to the old stock ones.

I now have a low side fitting that points directly at me when looking down at it from the passenger side. It's EXTREMELY easy to get to.

427V8

Me either! I like Duracool for the R12 systems. R12 makes a toxic gas when exposed to heat, Duracool just burns along with the oil.

Duracool is legal to use in a system that has been converted to 134.

But your AC man will most likely freak about Duracool It's made from propane and butane.

I figure there is what, 12 ounces in my AC system and I've got 20 gallons of gas behind me
Or in my motorhome I have 18 ounces of duracool and 50 gallons of gas and 40 gallons of liquid propane.

What was the problem again?

impalaman

Just to follow up. The solid brass 90 degree R134 adapter fitting I installed on the compressor is still in use and works perfectly. I can use my gauges easily.

'75

What refrigerant did you end up using and how well does it work?

78VettePlus

Agree about the location of the drier, and the compressor bolt. Just been through all that, same thing, but I was converting to r134a from r12. I managed to get the valves out, but had to hunt down a right angle fitting for same reason as you. Even the new repop hose and manifold sets have the same r12 fittings in the same bad location. Crazy! The low pressure fitting should be right near the high pressure fitting.

peace out, glad you got your problem sorted out. Hey, I hear that the military just uses CO2 as the refrigerant. If they get a shot in the engine bay, the refrigerant can act as a fire suppressant. Not sure it would be very efficient at cooling though?