Another A/C thread - tying up the loose ends

[71CHEVYSHORTBED402]

Well, less O-rings & the tiny hard line, I've learned how to assemble an A/C system. With board assistance of course. Anyway, hopefully the 67-72 Chevy brain trust can assist in tying up the loose ends. I plan for a R12 to R134A conversion.

1. HOSES: If you can get past the make-shift caps, how about the condition of these hoses & tubes? I didn't even wipe them down. They've been packed away since 93. With little effort, they'd look right off the showroom. At any rate, safe to say it's a good idea to replace the hose lines anyway? I could have done a better job of storing them, and they may not be reliable for R134A anyhow.

2. TAPE: Check out the tape job in the first picture. Seen this before?

3. TUBES: What's a good method for cleaning the insides of the tubes?

4. O-RINGS & Other: Where are O-rings used? Any additional "unseen" parts used to slam this together? IF YOU HAVEN'T ALREADY YOU CAN DISREGARD THIS NONSENSE.

5. "SLOP" & TINY HARD LINE CONNECT: Reference picture 2. What's the "slop" around the top tube of the core? More than that, how is the tiny hard line connected onto that tube? I assume it's not part of the core, being you can restore or replace the expansion valve.

6. EVAPORATOR CORE: While it looks great, if I recall, the rear of the POA valve and below the expansion valve were open for a stint. That and the A/C system has been disconnected from these points for decades, which may mean the evaporator core dried up. Are replacement cores of good quality, or is it better to have the original professionally refurbished?

7. POA VALVE: I believe the original POA valve works with R134A as well, it's a matter of calibration variance. I'd like this to appear as original as possible, do replacement POA valves look the same or close, or is it better to have the existing POA valve rebuilt?

8. EXPANSION VALVE: The original expansion valves work with R134A as well, right?

Other than that, happy to say I had saved all the parts less one clamp and the drier mount screws. But that's what I bought the 72 for........... . For what it's worth, I plan to replace the drier & condenser, and of course O-rings. All input appreciated, thank you.

[rsgt]

On one of my cars I took the tape off of the hose and found an extra key to the car.

[FirstOwner69]

Replace the hoses. They are not that expensive. At minimum, you'll have to replace the most expensive one with the muffler since the attachment point for the Freon is different for 134A. I also seem to recall reading here that 134A needs a different hose material... not sure of that though.

The black stuff you refer to as "slop" is factory. That's the way it was done. You can buy new stuff if you want. I bought some from Classic Industries but didn't use it. The original cleaned up fine.

The cute tape tie didn't appear on my truck. They used straps like the one in the first picture below in a couple places to retain the A/C power wire to the compressor. However, the terminal on the wire that goes to the compressor had a crappy tape wrap job.

I bought new aluminum hard lines. Easier than cleaning them. All lines came with new O-rings.

I sent my original receiver drier to Old Air to be restored. When they re-welded the top to the "can" they did a job that would embarrass a high school welding student. I sent them another receiver drier, and they did a decent job. The resto cost a lot more than a new drier. Before I decided to go that route, I bought a new drier that came marked for 134A which I didn't use since I stayed with with R12.

I did nothing with my expansion valve. I don't know if 134A requires a different one.

I took my condenser to a shop to have it pressure tested and flushed. They also painted it.

I didn't have to convert my POA since I stayed with R12.

I bought all the lines at Classic Industries when they were having a sale. Everything was made by Old Air.

Other than the restoration of the drier, I thought the prices were quite reasonable.

I put it all together then took it to the restoration shop that did the body work and paint to charge the system with R12 I supplied.

Jim

[71CHEVYSHORTBED402]

Originally Posted by rsgt

on one of my cars i took the tape off of the hose and found an extra key to the car.

bam!

[71CHEVYSHORTBED402]

Replace the hoses. They are not that expensive. At minimum, you'll have to replace the most expensive one with the muffler since the attachment point for the Freon is different for 134A. I also seem to recall reading here that 134A needs a different hose material... not sure of that though. I believe that's so Jim. It's that or anticipation the hose is worn out. Either way, I'll replace them.

The black stuff you refer to as "slop" is factory. That's the way it was done. You can buy new stuff if you want. I bought some from Classic Industries but didn't use it. The original cleaned up fine. Perhaps a heat gun and putty knife it's like new again? Makes sense. I'll do just that to the 72 tomorrow, see how the tiny hard line is connected. I imagine a nut, but have never seen one.

The cute tape tie didn't appear on my truck. They used straps like the one in the first picture below in a couple places to retain the A/C power wire to the compressor. My 72 has a black strap on the hose near the compressor flange.

However, the terminal on the wire that goes to the compressor had a crappy tape wrap job. Bastards

I sent my original receiver drier to Old Air to be restored. When they re-welded the top to the "can" they did a job that would embarrass a high school welding student. I sent them another receiver drier, and they did a decent job. The resto cost a lot more than a new drier. Before I decided to go that route, I bought a new drier that came marked for 134A which I didn't use since I stayed with with R12. I recall the conversation.

I did nothing with my expansion valve. I don't know if 134A requires a different one. I don't believe it does. Just looking for confirmation.

I took my condenser to a shop to have it pressure tested and flushed. They also painted it. [COLOR="blue"]Mine is tweaked. Word is the original condenser works with R134A, but not as well as a new serpentine. Perhaps not as well as a new tubed condenser too, considering most of ours have been mounted 50 years./COLOR]

I didn't have to convert my POA since I stayed with R12. I recall from a previous conversation, it makes practical sense you never convert. As far as I know, "conversion" is limited to calibration. Unless I stand corrected, the original POA calibrates to R134A. Still wondering out there, if I should rebuild the old POA, or replace with a "looks genuine"?......Probably rebuild.

I bought all the lines at Classic Industries when they were having a sale. Everything was made by Old Air....Other than the restoration of the drier, I thought the prices were quite reasonable. Will look for that.

I put it all together then took it to the restoration shop that did the body work and paint to charge the system with R12 I supplied. Nice one stop shop.


Sure is a clean truck Jim. Appreciate the response.





What the?

[71CHEVYSHORTBED402]

Originally Posted by rsgt

On one of my cars I took the tape off of the hose and found an extra key to the car.

SON OF A GUN...........Look what I found. Now I see the purpose. Edit: Checks out, it's the original key. What a great "safety" feature. Ponder that for a moment and compare to our society today. Perhaps its just a coincidence, but I'm leaning to factory or dealer installed. Still seems a bit odd.

[71CHEVYSHORTBED402]

The expansion valve just clamps onto the core tube. I suppose it's temperature operated.

I also determined when you remove the PAO valve, you break your $1 reading glasses and cut the bridge of your nose.

[tdangle]

I just finished rebuilding my AC. New hoses as the old ones would not hold a vacuum. Checked the POA valve, didn't have to adjust as it was operating at 27 already. Replaced all O-Rings, new dryer, blew out evap and condenser with compressed air and flush. New thermal goop take on the expansion valve bulb. Original compressor. Drained and changed the oil to Ester Oil. Vacuumed for a couple of hours and recharged with R134a. Seems to work OK so far. Looks 100% original. I couldn't find the conversion valves that screw on to the fittings, so I just left it alone. I know its 134, no one else does and no one else will be working on it.

[71CHEVYSHORTBED402]

Originally Posted by tdangle

I just finished rebuilding my AC. New hoses as the old ones would not hold a vacuum. Checked the POA valve, didn't have to adjust as it was operating at 27 already. Replaced all O-Rings, new dryer, blew out evap and condenser with compressed air and flush. New thermal goop take on the expansion valve bulb. Original compressor. Drained and changed the oil to Ester Oil. Vacuumed for a couple of hours and recharged with R134a. Seems to work OK so far. Looks 100% original. I couldn't find the conversion valves that screw on to the fittings, so I just left it alone. I know its 134, no one else does and no one else will be working on it.

Sounds good to me. Can I ask how these are oiled, and where? Vacuumed a couple hours?


Expansion valve bulb.........Noted.

[tdangle]

I took the compressor off opened the drain plug and drained the oil while turning the shaft. Then refilled using Ester oil as it is somewhat compatible with mineral oil. Pag oil will gum up when in contact with remaining mineral oil. Reinstalled everything and hooked up a vacuum pump to the system this evacuates the system removing moisture in the system 29" of vacuum for a few hours

You may want to put everything together and take it to a shop to charge. I like trying to do this stufff myself

[71CHEVYSHORTBED402]

Originally Posted by tdangle

I took the compressor off opened the drain plug and drained the oil while turning the shaft. Then refilled using Ester oil as it is somewhat compatible with mineral oil. Pag oil will gum up when in contact with remaining mineral oil. Reinstalled everything and hooked up a vacuum pump to the system this evacuates the system removing moisture in the system 29" of vacuum for a few hours

You may want to put everything together and take it to a shop to charge. I like trying to do this stufff myself

Thank you for that info. Yep, sounds to me I'll have someone do it. I'm replacing the core, lines, compressor, drier and condenser, but I suppose oiling is required anyhow. Perhaps it's part of the service.