AC vacuum frustration

[Shran]

I am may just have to have a shop look at this. I replaced the evap core and accumulator again… and it is no better on the vacuum side of things but now loses nitrogen faster than before. I can’t find an obvious leak with my soapy water test and the only thing that I haven’t replaced is the compressor but it wasn’t leaking before all this. I’m tempted to have a shop run dye through it and at least tell me where the issue is… thoughts? Really at a loss and tired of throwing parts at it.

 

[alwaysFlOoReD]

Get your own dye and black light? I think I paid about $8 for a small bottle of dye for oil leaks. Maybe it would work for you?

 

[Uncle Gump]

I would be tempted to just charge it up with refrigerant with dye. Maybe even some with a little sealer. Then just let it run and cycle.

 

[mikkelstuff]

What O-rings are you using? I was having trouble sorting out A/C problems with my '75 Ranchero while using those green O-rings from NAPA. I finally found that I could not reuse those green O-rings and had to source the good black neoprene O-rings before I could solve the other A/C problems.

 

[Shran]

I am using the green O rings, each of them has been changed at least once if not twice. I believe you must use the green HNBR o-rings for R-134a? Black were OK for R12?

I am not afraid to shoot some dye in it myself, but, to function correctly, the system must be vacuumed down at least somewhat, right? I can't get it to hold a vacuum for more than a very short period and I am afraid if I pull a vacuum for more than a few minutes I will ruin the accumulator by pulling outside air in through whatever is leaking. Then I have to worry about evacuating the system, fixing whatever is wrong and recharging it... hate to burn $30 in refrigerant just as an experiment.

 

[Uncle Gump]

I guess I should have read this a little closer. Sounds like you took two steps forward and four or five back.

Any of the dye I've ever used has to be circulated through a functioning system.

 

[mikkelstuff]

What about the compressor front seal? Any way to shut it out. They used to put valves on the compressor lines but those were eliminated years ago.

 

[Shran]

What about the compressor front seal? Any way to shut it out. They used to put valves on the compressor lines but those were eliminated years ago.

After ruining one of my three manifold sets and burning up a bottle of soapy water, two hours and about $20 of nitrogen I think that's where the frickin leak is.

I gave it a nice shot of about 225psi nitrogen and I can hear it leaking out of there now. I don't think I had enough pressure in there before to hear it and my hearing is not the greatest anyway. So I either found a leak or made one... What's another buck fiddy for a new compressor, at this point, might as well try.

 

[mikkelstuff]

Glad you found at least this possible leak. As a "junk collector" I think you should build a compressor bypass fitting for the vacuum test. Then show us how to make one.

 

[Shran]

I'm pretty certain that it was the compressor front seal. New one arrived yesterday, held vacuum overnight and I charged it this morning!!! Fingers crossed that it's fixed!