Re: 2007 Ford F350 AC issues.
Posted: Sat Aug 13, 2022 7:29 am
Tim is the site owner, and runs AMA, Arizona Mobile Air. He is very good.
That procedure is such that we suggest it is OK for a fresh clean dry system that has not been flushed and blown dry.
Flushing and blow drying with shop air is a whole different story, Shop air is LOADED with moisture. I have a $800.00 drier connected to my shop air because 1) we do AC work here and 2) we also have a paint booth and paint cars. Moisture in an air line can destroy a paint job really quickly.
I will surmise that no DIY people on here have such a drier.
Why do you think that JohnHere suggested nitrogen as a first choice? (it is already dry)
John routinely suggests a vac time of 1 hr, since the vast majority of our posters come here either after a comp has grenaded or when WE tell them it has grenaded, and they are gonna have to flush and dry.
I myself suggest what I know to be best practice here on an established system. None of us gets to work on a virgin system very often. Your method is analogous to the stock market, ie, past performance is not a predictor of future performance. I also use a vacuum gauge, and the ideal vacuum is 500 microns or less. I can tell you that you cannot get to 500 in 30 or 45 minutes. The numbers on the low side gauge are just an estimate, kind of like measuring crankshaft bearings with a yardstick.
John may stop by to render an opinion, that is up to him.
Posters can do what they choose.
That procedure is such that we suggest it is OK for a fresh clean dry system that has not been flushed and blown dry.
Flushing and blow drying with shop air is a whole different story, Shop air is LOADED with moisture. I have a $800.00 drier connected to my shop air because 1) we do AC work here and 2) we also have a paint booth and paint cars. Moisture in an air line can destroy a paint job really quickly.
I will surmise that no DIY people on here have such a drier.
Why do you think that JohnHere suggested nitrogen as a first choice? (it is already dry)
John routinely suggests a vac time of 1 hr, since the vast majority of our posters come here either after a comp has grenaded or when WE tell them it has grenaded, and they are gonna have to flush and dry.
I myself suggest what I know to be best practice here on an established system. None of us gets to work on a virgin system very often. Your method is analogous to the stock market, ie, past performance is not a predictor of future performance. I also use a vacuum gauge, and the ideal vacuum is 500 microns or less. I can tell you that you cannot get to 500 in 30 or 45 minutes. The numbers on the low side gauge are just an estimate, kind of like measuring crankshaft bearings with a yardstick.
John may stop by to render an opinion, that is up to him.
Posters can do what they choose.