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  #1  
Old 08-11-2005, 09:45 PM
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AC rebuild complete ....... finally!

The long story began here:

A/C Low and High side pressures?

So after being forced to admit that I had allowed a shop to put Freeze12 in last year and now faced with a hot summer and a system that was barely cooling the air, I proposed the following:

Quote:
Ok, here is the plan:

1. remove remaining old freeze12;

2. replace expansion valve and consider replacing hoses; repair shrader valve core on low side; replace E.T.R. switch; replace 0-rings and lubricate with Nylog assembly lube;

2. flush entire system with "mineral spirits first and then follow that up with regular a/c system flush to get out the residue" and then "blow, blow, blow" (LarryBible--04/14/2005)

3. vacuum test; I don't have the equipment to pressure test with dry nitrogen and do not have an electronic leak detector; and

4. Charge with PROPANE -- sorry, couldn't resist that -- charge with correct amount of R-12. I don't need a 30lb supply -- is there a better source for small cans other than e-bay?

Now all I need is a few days off work.
I never got the few days off and I suffered along and even resorted to driving the Durango (13 mpg sucks) some. Finally, the compressor developed a massive leak around the outer seals. So I did all of the above and completed the vacuum test 9 days ago. But the R12 I had bought on E-bay did not arrive until today. The system still held the same vacuum it held 9 days ago. So I charged up the system with 2.9 lbs of R12. BTW it was 95 F according to the Durango temp guage this afternoon when I shot the photo below.

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AC rebuild complete ....... finally!-mvc-002s.jpg  
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  #2  
Old 08-11-2005, 10:38 PM
LarryBible
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Wow, you've turned into quite the a/c guru! Good work.

I would only point out one thing, and it could be that I don't understand exactly what you did. If you pumped the vacuum and waited nine days, then charged, that's not the best plan. It probably is okay, and not a bad way to test an empty system for leaks. What would be best would be to evacuate again before charging.

The reason is that a system under vacuum will pull in air and moisture if there is even a tiny leak unlike a charged system which is under pressure so nothing can get in. Since the weather is hot, evacuating one last time before charging would have boiled off any slight moisture in relatively short order.

Just thought I would throw that in so you will know.

Congrats on a job well done,
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Old 08-12-2005, 08:12 AM
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Quote:
So I did all of the above
Does this include replacing the hoses?

Danny
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Old 08-12-2005, 09:21 AM
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Quote:
Originally Posted by dannym
Does this include replacing the hoses?

Danny
Maybe I should have replaced the hoses, but I didn't. Hoses appear sound and I did leak test extensively before starting the rebuild. I did replace the compressor, condenser (found leaks at 2 of the U section joints), and expansion valve. I did drill out the old expansion valve and used it for flushing.

I did "borrow" the Autozone vacuum pump again and re-vacuum yesterday before charging with the R12.
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Old 08-12-2005, 09:36 AM
LarryBible
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I think that your approach on the hoses is correct. Unless they are leaking there is no need to replace them for a preventive maintenance step. That would be like replacing your car because the old one might break. If it ain't broke don't fix it. When a hose leaks replace it.

Glad to hear that you reevacuated before charging. I think that leaving the vac on for 9 days was a very good poor boy leak check step, before committing the refrigerant.

Again, good work,
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  #6  
Old 08-12-2005, 09:38 AM
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Yeah, good job.

What pressures are you running at?

Danny
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  #7  
Old 08-12-2005, 11:04 AM
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Well , it looks like I think you did a much better job than Larry... I have no idea where he is coming from on the leak deal...
There are only two ways which a properly pulled vacuum will go away... one is a hole in something... or a leak past a seal...
OR that their was moisture in the oil which boiled off ...
If you pulled a good vacuum, read your guages reasonably close at the first and last of that operation and they had not moved I think you did a good job.
Remember on taking the picture of your thermostat... the low temperature is taken with the interior fan on LOW... that will give you closest to the evap terperature for your thermometer ....
Unless there is air taken into the system you do not have to assume that moisture entered it ...
However, it never hurts to vacuum more.. so doing it again immediately before charging is great... and remember to put newly opened oil into your vacuum machine...

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