AC question

[sparky0798]

I am finally getting around to working on my ac system. It currently has nothing in it and is still set up for R12. I am planning on keeping it that way for now since I have some left. My question is, before I pull a vacuum on it should i change anything out as far as seals, orifice tube, accumulator etc to bring the system up to snuff? It blew somewhat cool 5 years ago when I bought the car. Thanks

 

[LelandLs6]

If you have the time and money I would deffinetly replace the o-rings and any other parts you second guess about

 

[sparky0798]

Yeah I thought the same thing. I have most of the stuff just not the time lol. I've never had the system open but it looks like the accumulator may have been changed in the past. I think my valve on the high pressure side may be bad as well. Can you get replacements at the parts store and are they for ac systems or just a regular tire valve stem?

 

[LelandLs6]

Only tire valve stems I've seem are rubber?? So I would think it's for the ac system specifically. And you should be able to buy individual parts at say autozone or oriellys I just wouldn't bet on it looking like your oem part. But as long as your compressor and drier are good I think you'll be in the clear.

 

[sparky0798]

Thanks. Sorry I meant the schrader valve on the ac line. I heard some hissing from it before

 

[LelandLs6]

Oh lol I read your comment wrong... Maybe try using one of those tools to tighten the stem like they have for the tire stems? I'm not entirely sure if they're the same but if it is leaking I'm sure you already know that's really bad.

 

[Raeban]

The orifice tube is too cheap not to replace and I would change the accumulator while there to. Refrigerant prices are too high not to swap those two parts IMO.

 

[sparky0798]

Makes sense. What orifice tube should I use if staying with R12?

 

[Raeban]

I'd stick to the standard orifice tube and avoid the variable ones. The original replacement version should be a factory air number 38623 IIRC.

 

[sparky0798]

Ok thanks for all the help

 

[earlbrown]

I was thinking there was a Ford orifice that was supposed to work better. Or is that just when using less efficient 134?

 

[cruzn57]

schrader valves for a/c ARE different than tire valves!

your tire may hold 35psi ,
your a/c goes to over 175psi, (or more)
they (a/c) are not rubber, but something compatible with compressor oil.
if you use a tire valve, IT WILL LEAK, maybe not right now, , but it will!
O riely 's shows them online.

 

[sparky0798]

I think the ford orifice is only used when doing a conversion.

About 2 years ago my buddy pulled a schrader valve out of his tool box and replaced mine. I bet he used a tire one and that is why it's leaking now.

 

[sparky0798]

When changing out the accumulator should I put any oil in the new one or on the o-rings? If so, do I use mineral oil for r12 systems and how much? Thanks in advance

 

[Raeban]

If it is R12 mineral oil should be the correct type. 8.0 0z for a full charge IIRC but just changing the accumulator won't require that much. It's always a bit of a guessing game when your system has leaked down because inevitably you will lose some oil as well. If you don't want to start over I would add 1 Oz to the suction hose personally. In regards to the ford orifice tube they do fit and do work, and are supposed to give colder evap temps due to a smaller orifice, but a well respected A/C guy in my area taught me a long time ago that if you are going back with the original setup to stick with the original design on A/C systems. The last thing you want is an evaporator freezing up on low fan speeds on a hot day. Also, make sure you do a leak down test under vacuum for a hour or so. A common area for leaks is at the compressor and R12 is way too expensive to be making that mistake.

 

[sparky0798]

I did a leak down test today before changing anything out and was only able to get 10psi hg. It took about 5 min for it to go back to 0 once I shut the valves and disconnected the pump. What would be my next step? Put some dye in the system with a little freon?

 

[earlbrown]

I don't understand. Hg is measured in inches.

At any rate if you had any kind of vacuum and it took 5 minutes to equalize, that's a sure sign of a leak.

If you didn't start with that much vac and it equalized in 5 it might not be as dramatic. Is this one of those instances where you have to learn when not to trust your tools?

 

[captndave737]

I did a leak down test today before changing anything out and was only able to get 10psi hg. It took about 5 min for it to go back to 0 once I shut the valves and disconnected the pump. What would be my next step? Put some dye in the system with a little freon?

You have a leak somewhere. You have to find and fix it. If it doesnt hold vaccum it wont hold pressure. You should pull vavuum on the pump close the valves and come back a day later and see no change. Thebsystem shouldbe sealed. Last time I had that problem it was the seal on a new compressor!!!

 

[sparky0798]

Can I put some 134a with dye in my system to find my leak since its going to leak out anyway and is cheaper than r12?

 

[captndave737]

I dont know how thet mix. I converted mine to 134 years ago. Some say it's les efficent but mine has been better than the R12 ever was. You have to replace the switch on the acumulator because R134 runs at higher pressure than R12.