AC system charging oopsie ... ?

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Feb 20, 2022
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Took the '77 F-100 in to get the AC system swapped to R-134. Long story short, shop read the conversion table wrong and put over twice the correct amount of R134 into the system.

The compressor locked up and the belt squealed, pressure went off the scale.

Good news is they were able to pull vacuum and remove the 134, so it would seem that the system doesn't have a leak.

What's the chance that the old York compressor will live to cool another day?

This is a very frustrating experience to say the least.
 
Those compressors are pretty tough. But.... Did they pull the York off and dump out the old mineral oil, then refill it with 10 oz of ester oil before they put it back on?

Did they change the receiver dryer? How about the hoses? You certainly don't expect 45 yr old hoses to work with R134a do you?

If it has a serpentine type condenser those won't usually work with r134a. It also sounds like they did not install a high pressure cut out switch which is required when retrofitting a car that did not originally have one.
Total r134 a capacity on that truck should only be about 24oz. You would think they would have known this before trying to stuff 3 pounds in it
 
Took the '77 F-100 in to get the AC system swapped to R-134. Long story short, shop read the conversion table wrong and put over twice the correct amount of R134 into the system.

The compressor locked up and the belt squealed, pressure went off the scale.

Good news is they were able to pull vacuum and remove the 134, so it would seem that the system doesn't have a leak.

What's the chance that the old York compressor will live to cool another day?

This is a very frustrating experience to say the least.
Those reciprocating compressors look pretty sturdy, possible nothing happened but if anything maybe valves and seals?
 
seems like they should be responsible for a new compressor and any repairs from their mistake that are needed?

maybe even a warranty if it blows up short time from now?
Agreed. We will have a discussion when I pick it up.
 
Those compressors are pretty tough. But.... Did they pull the York off and dump out the old mineral oil, then refill it with 10 oz of ester oil before they put it back on?

Did they change the receiver dryer? How about the hoses? You certainly don't expect 45 yr old hoses to work with R134a do you?

If it has a serpentine type condenser those won't usually work with r134a. It also sounds like they did not install a high pressure cut out switch which is required when retrofitting a car that did not originally have one.
Total r134 a capacity on that truck should only be about 24oz. You would think they would have known this before trying to stuff 3 pounds in it
They pulled the oil out and replaced ... as far as the oil in the reservoir, no ... I believe I can do this myself without opening the system up? Honestly I want them to do as little as possible at this point.

Thanks for the input on the high pressure switch. Sounds like I need to find a shop that knows what they're doing.

They didn't think the hoses needed replacement. We'll see. If it doesn't hold refrigerant I'll swap them out. Good thing R134 is way cheaper than r12 these days.

Honestly this whole thing is less than satisfying to work with. Seems that there's so much potential for issues on old AC systems. Hoping for the best.

Thanks for the input! Don't know a lot about AC and apparently the shop doesn't either. In a low income part of MS so shops aren't used to doing things right, it would seem.
 
They pulled the oil out and replaced ... as far as the oil in the reservoir, no ... I believe I can do this myself without opening the system up?

They didn't think the hoses needed replacement. We'll see. If it doesn't hold refrigerant I'll swap them out.
No. You must remove the compressor and dump out the oil. Not sure what you mean by pulled out and replaced the oil. Being so old it's likely that most of the mineral oil is gone anyway. If so then the oil level needs to be checked and filled inside the body of the compressor before you vacuum or charge it.

Do the hoses use worm clamps or crimped ends?
 
Looks like I'm just going to be unhappy with the whole job. They've already run the system and say it's working. Guess we'll hope for the best at this point.
 
The high pressure switch was not required on r12 cars. It's required on r134a cars because that refrigerant can build dangerous high pressures in an instant. It will work without it but is a govt requirement when retrofitting to r 134a.

If it had been installed it would have turned the compressor off instead of allowing it to lock up. And you would not be asking about damage done to the compressor.

 
The high pressure switch was not required on r12 cars. It's required on r134a cars because that refrigerant can build dangerous high pressures in an instant. It will work without it but is a govt requirement when retrofitting to r 134a.

If it had been installed it would have turned the compressor off instead of allowing it to lock up. And you would not be asking about damage done to the compressor.

Thanks for the link. Can that be installed without evacuating the system?

Things I've learned:

-trust no one
-especially car shops
-consult BITOG for all things mechanical

Hoping for the best.
 
Thanks. I'm seeing a vacuum and recharge in my future. Lines, high pressure switch... there will be quite a list.
 
Took the '77 F-100 in to get the AC system swapped to R-134. Long story short, shop read the conversion table wrong and put over twice the correct amount of R134 into the system.

The compressor locked up and the belt squealed, pressure went off the scale.

Another advertisement for a DIY instead of taking it to a "professional" mechanic.
 
Another advertisement for a DIY instead of taking it to a "professional" mechanic.
Yeah. Can't quite justify buying a R12 conversion setup for one use though.

Guess this is why I always do work myself whenever possible.
 
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