My Maintenance Schedule has stripped a gear...

[JR]

AC service on the 1/2 ton today. Sure helps having a friend with a machine. Ran some die in it also. View attachment 112453

I sure would love to get me one of them rigs. I was looking hard at them last year after getting jacked around too many times to count on AC work. Being a novice I got cold feet on that big of investment and ended up buying a pump and a decent set of gauges to get me going. Gotta start somewhere eh? I don't think I can do much worse than some of the hack jobs I've paid for over the last 5 years.

 

[jgillott]

I sure would love to get me one of them rigs. I was looking hard at them last year after getting jacked around too many times to count on AC work. Being a novice I got cold feet on that big of investment and ended up buying a pump and a decent set of gauges to get me going. Gotta start somewhere eh? I don't think I can do much worse than some of the hack jobs I've paid for over the last 5 years.

What I like about Eric's machine is that is is pretty much foolproof. Attach the lines, program the amount of refrigerant for the vehicle (it is accurate to 1/100th of a kilogram), push start and it evacuates the system and then recharges it to the proper level. Almost impossible to mess up.

This is the first charge on that truck which is now 9 years old. It was still cooling some, but not like it should. It was definitely down some but doesn't have any obvious leaks. Put the dye in this time. If it does leak back out, we will hopefully be able to locate the leak.

 

[JR]

J, fool proof costs money

 

[TFucili]

I have had employees... there is nothing foolproof...

 

[jgillott]

I have had employees... there is nothing foolproof...

I'll modify my statement........pretty much foolproof for someone working on their own vehicle who cares about the result.

Is that better? Lol

 

[Dan_69GTX]

I sure would love to get me one of them rigs. I was looking hard at them last year after getting jacked around too many times to count on AC work. Being a novice I got cold feet on that big of investment and ended up buying a pump and a decent set of gauges to get me going. Gotta start somewhere eh? I don't think I can do much worse than some of the hack jobs I've paid for over the last 5 years.

So, how did that work for you? I don't think I ever saw an update.

The other week my Dad thought his car wasn't cooling well. I know the compressor seal has a very small leak. So I put the gauges on it, temp probe in the middle vent, LARGE shop fan in front of the car - blowing 47* air. Sorry Dad, won't get much better than that!

 

[Dan_69GTX]

I have given up on the "do-it-all" machines. I personally haven't had good luck with them. Sometimes they work fine other times it over charges, under charges, etc. Some measure removed oil and replace, some don't. And of course that feature doesn't work if you add a filter to collect oil, contaminants (like sealants), etc. Plus they get really out of wack when some careless employee drags it across the parking lot bouncing it along the way, totally screwing up the scale.

So I always do the good ol fashion way - recovery unit, gauges, scale, filters, etc all separate entities.

 

[Wayne M.]

I use an older robinair station. As long as you keep it maintained, and the scale calibrated, this machine is fantastic. It does a leak check. Dial in the amount of refrigerant and oil, and it’ll charge one side or the other or both. If you suspect a leak, just suck it down to see. It separates the oil so you have an idea on what to put back, and following this idea, I’ve always had success.

 

[JR]

So, how did that work for you? I don't think I ever saw an update.

The other week my Dad thought his car wasn't cooling well. I know the compressor seal has a very small leak. So I put the gauges on it, temp probe in the middle vent, LARGE shop fan in front of the car - blowing 47* air. Sorry Dad, won't get much better than that!

Only used it once so far but all was well through the end of the cooling season. The blend doors went TU over the winter - blows hot only - so that's on the list now. Not looking forward to that at all on that little car....

 

[jgillott]

I use an older robinair station. As long as you keep it maintained, and the scale calibrated, this machine is fantastic. It does a leak check. Dial in the amount of refrigerant and oil, and it’ll charge one side or the other or both. If you suspect a leak, just suck it down to see. It separates the oil so you have an idea on what to put back, and following this idea, I’ve always had success.

With that RTI machine, I pulled it down to -1 bar on Saturday and it held vacuum until I released it.

 

[Dan_69GTX]

I had an old R-12 robinair recovery unit that worked GREAT! Would recycle the refrigerant to remove moisture, etc. I ended up getting rid of it just because of how little I used it and it took up a lot of space. Still do some R-12 - only one around that will. I only do it for folks I know and typically for older cars (last one was a 64 Caddy).

Here is what I use now to recover - great for all refrigerants. Got it for a very reasonable price and it is small and portable.
http://appioninc.com/products/g5features.html

 

[Dan_69GTX]

Only used it once so far but all was well through the end of the cooling season. The blend doors went TU over the winter - blows hot only - so that's on the list now. Not looking forward to that at all on that little car....

Glad it worked well!

Maybe just put a valve in the line for the heater core, close it, and call it done! I believe most all cars would always pass air through the evap all the time for dehumidification, so you should be ok.

 

[jgillott]

I had an old R-12 robinair recovery unit that worked GREAT! Would recycle the refrigerant to remove moisture, etc. I ended up getting rid of it just because of how little I used it and it took up a lot of space. Still do some R-12 - only one around that will. I only do it for folks I know and typically for older cars (last one was a 64 Caddy).

Here is what I use now to recover - great for all refrigerants. Got it for a very reasonable price and it is small and portable.
http://appioninc.com/products/g5features.html

My Corvette is still R-12. I need to either convert it to 134a or find someone who is still willing/able to work with the 12.

 

[JR]

Glad it worked well!

Maybe just put a valve in the line for the heater core, close it, and call it done! I believe most all cars would always pass air through the evap all the time for dehumidification, so you should be ok.

I've actually thought of this but Im not sure how much the wife would appreciate having to climb under the hood for a/c and heat/defrost duty. She's down to driving it one day a week and I drive it to work the other days, so i just may try it out. Ive even got some extra 1/2"ball valves laying around. Just need a couple of npt to hose barb fittings to be in business.

 

[Dan_69GTX]

My Corvette is still R-12. I need to either convert it to 134a or find someone who is still willing/able to work with the 12.

I recommend keeping with R-12 if you can. However, not all folks can. If you do change it over find someone that will do it correctly. Around here most folks just remove what is left of the R-12 (sometimes), put the R-134a valve adapters on the ports, and recharge. Yea, it sorta works, but for how long and it isn't that efficient.

Summary of what needs to be done: (most shops don't do this).
- reclaim any R-12
- remove as much mineral oil as possible. (will require removing compressor and flushing rest of it).
- Change out the orifice/ expansion valve with one designed for R-134a (will be a smaller orifice).
- Change out any pressure switches with one designed for R-134a.
- add a high pressure cutout switch.
- swap in a receiver/drier or accumulator with one that is compatible with PAG/Ester oil.
- If any hoses have a leak make sure the new hoses are for R-134a (NOS hoses are not!)
- new gaskets/o-rings must be for R-134a
- Add appropriate amount of Ester oil.
- Add R-134a - I start at about 80% and add as needed to it cools good.

I've had decent luck doing that and the vehicle cools and the system lasts. Note that ANY leaks you have will be worse with R-134a since R-134a has a smaller molecular structure.

I use an identifier on ALL vehicles. Most that have been converted show some R-12, which shows they were not converted properly.
https://refrigerantid.com/products/automotive-refrigerant-identifiers/

It is also amazing how many systems have some form of combustible products in it (propane, butane, etc). Many of the EPA approved R-12 replacements contain some combustible material. EPA approved doesn't mean safe to use - go figure.

Here is a good link to what I just said.
https://www.sanden.com/objects/retro.pdf

 

[jgillott]

I recommend keeping with R-12 if you can. However, not all folks can. If you do change it over find someone that will do it correctly. Around here most folks just remove what is left of the R-12 (sometimes), put the R-134a valve adapters on the ports, and recharge. Yea, it sorta works, but for how long and it isn't that efficient.

Summary of what needs to be done: (most shops don't do this).
- reclaim any R-12
- remove as much mineral oil as possible. (will require removing compressor and flushing rest of it).
- Change out the orifice/ expansion valve with one designed for R-134a (will be a smaller orifice).
- Change out any pressure switches with one designed for R-134a.
- add a high pressure cutout switch.
- swap in a receiver/drier or accumulator with one that is compatible with PAG/Ester oil.
- If any hoses have a leak make sure the new hoses are for R-134a (NOS hoses are not!)
- new gaskets/o-rings must be for R-134a
- Add appropriate amount of Ester oil.
- Add R-134a - I start at about 80% and add as needed to it cools good.

I've had decent luck doing that and the vehicle cools and the system lasts. Note that ANY leaks you have will be worse with R-134a since R-134a has a smaller molecular structure.

I use an identifier on ALL vehicles. Most that have been converted show some R-12, which shows they were not converted properly.
https://refrigerantid.com/products/automotive-refrigerant-identifiers/

It is also amazing how many systems have some form of combustible products in it (propane, butane, etc). Many of the EPA approved R-12 replacements contain some combustible material. EPA approved doesn't mean safe to use - go figure.

Here is a good link to what I just said.
https://www.sanden.com/objects/retro.pdf

I appreciate the very detailed information. Thank you. I would love to stay with R12. We had one gentleman here that used to service them. He has since retired and I haven't heard of anyone else on the area that does the work.

Additional question for you. I haven't investigated where the leak is on my Vette. But, with the amount of oil hanging from the compressor, I wouldn't be surprised if it was an internal compressor leak. What would you recommend doing if that is the case? Would there be a better compressor alternative to get at that point to handle the 134a if I need to go that route or simply stick with an original replacement?

 

[Dan_69GTX]

Depending on the compressor it is most likely the shaft seal. Some compressors had a body o-ring that would leak.

So, what year is your vette? Is the compressor an original style or has it been changed? If changed - any idea what the compressor is?

 

[jgillott]

It's a 1987. All original.

 

[Dan_69GTX]

It should be an "R4" compressor then.

Yes, there are updates for converting to Sanden compressors. However, I've never done a Vette, so you'd have to check and see if adapters are available for your application.

Whatever you do, buy the best compressor you can get.

Remember, that as the A/C system loosed charge, you also loose the ability to lubricate the compressor. The refrigerant carries the oil with it. Low on refrigerant, you starve the compressor and quicken it's demise. If the compressor goes out, you need to replace a lot of other things since it will contain debries in them. Remember, it is a close loop system with no filter!

 

[Dan_69GTX]

A place to start looking:
https://www.vintageair.com/