Help on installing an almost completely new AC system

[njs2247]

My compressor seized on me and since I have 111,000 on my truck, looks like I will be fixing the issue myself.  I will be changing out the compressor, condenser, accumulator and expansion valve. I am also going to replace the line that runs from the compressor to condenser just because it is known to leak. I also have that bracket GM came out with to decrease the vibration on said line. I just have a few questions before I tackle this job.

 

First of all, does anyone know if there have been any revisions done to the R134a capacity for these trucks?

 

Secondly, anyone know the total PAG oil capacity for the AC system on these trucks?

 

Lastly, can someone please tell me the torque specs for the various connections for the AC System?

 

Thanks in advance!

[silveradosid]

the total oil capacity is 8 ounces read this for each component air conditioning oil capacity.txt 15 to20 ft lbs for torque

[1SLOW1500]

Also make sure you have the new version of the ac line. It will have a small piece of wire loom on the rubber flex joint. Also look it up on YouTube. I saw a video of how to the system. If you dont already have one harbor freight sells the ac recharge gauges.

[njs2247]

Thanks for the info silveradosid. Just one question. Since I'll be replacing pretty much everything except for the high/low pressure lines and the evaperator and total capacity is 8oz, should I only add a total of 5oz of oil since 3oz could possibly still be in the evaperator? If that's the case, the compressor I got already has 5.07oz of oil in it. At least that's what the label on the compressor says, I still have to measure it.

 

I will be taking the high & Low lines off so I can flush them, I'm just not replacing them.

 

1Slow, the AC line I got is the newer one with the wire loom. Thanks for letting me know about that. Also, I rented the gauges and vacuum from Oreilly's. 

 

I replaced the condenser myself this past Summer, so I'm not too worried about the vacumm and recharge portion of this, just the installation of the new parts since I've never done it before.

[300 Blackout]

Tag. No info to help you but I’m interested in any info about this. I wouldn’t mind replacing the compressor before it takes out my new condenser.

[txab]

Flush the evap then add the appropriate amount, you'll know you've got the right amount of oil in the system. Be sure and pull a proper vacuum to check for leaks and to boil off moisture

[silveradosid]

agree with txab flush everything and start fresh 

[njs2247]

Good idea txab. Thanks for the help guys.

[njs2247]

So I was unable to flush the evaporator. Apparently they got a gorilla to tighten the torx screws on expansion valve!! Got one out, but stripped the other one. I've heard flushing ac with expansion valve on is not recommended and I didn't want to chance it. 

The good thing is that when I flushed the high and low pressure lines, there was no visible metal shavings. I was shocked because the compressor had a half dollar size hole on the side of it. Did a vacuum for about an hour and it held pressure for 45 minutes.

I will do a much longer vacuum tomorrow and see if it holds for over an hour. 

[txab]

Vacuum, not pressure.

[njs2247]

Oops. Yes, vacuum not pressure.

[njs2247]

Ok guys. Need some advice. When pulling a vacuum the vacuum only goes to -25, but it holds there when the vacuum is turned off. It held there for over an hour. I've disconnected and reconnected every line, but it still only pulls -25. All the lines have new o-rings too. 

 

Any ideas?

[Snowcamo]

Automotive compressor front shaft seals are not designed to hold a vacuum. However they will hold pressure just fine if you have a way to pressurize a system that would be a more reliable way to check for leaks. Mvac 609 vacuum requirements are only 0 psi.

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[njs2247]

Went and rented another vacuum and gauges, now vacuum is at -29. Thank god...

[Snowcamo]

To an HVACR tech -29 means nothing as it's microns we read. You'll likely not have any issues with the vacuum you pulled so put some 134a in and let er rip.

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