A/C orings

79jasper

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Well I bought the mt2526 oring set from autozone, 3 12 Oz cans of refrigerant, and 8 Oz of PAG oil with uv dye. (Incase the orings don't fix it)
Also I recall someone recommending a formula using ambient temperature to calculate high/low pressures. Anyone recall?
I've read 1.1×temp.
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79jasper

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And I think I maybe found the cause.
So this seems to have been leaking.
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Don't mind the wet oil on the end, that was from my fingers. Also it was only hand tight.
2nd possible cause. Where the line block comes into the pump, are there supposed to be orings there? Mine had none, but I put some in there. It was slightly oily.

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tbrumm

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jasper, in my Haynes AC manual, it lists the system pressure ranges for almost every vehicle. For the 1994 model year, the low side pressure for the F Series and Bronco is 28-45. The high side is 128-230. Obviously it depends on ambient temp. I was thinking the general guideline was ambient temp. plus 100 for the high side. @chris142 might be able to help. If I recall, he owns a rad. shop and does AC work too.
 

chris142

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@75-90f about 2x ambient on the high side.over that 2.2x ambient if running r134a
 

needlenose

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The only way to accurately charge the system is by weight, meaning use refrigerant scales. The pressures should really only be used to ensure the system is flowing/cooling properly. I bought a scale for around $120. Extremely sensitive and great for weighing other things for weight balancing etc.

I have bought oring sets from both Autozone and Oreilly. But an a/c compressor shop will have the best quality. They usually give you about 200 assorted. Whereas the auto shop gives you about 25. I've done 4 vehicles with my set from the compressor shop and I still have some left.

I was told when you charge that you should account for 1oz loss per can, and 1oz loss per charge from manifold and hoses. This is why the scales are so helpful. You know exactly(minus manifold loss) what's going in.

The nice thing about that pressure switch on the drier is that it has a schrader valve under it. You can remove it while the system is charged and replace the ring.
 

chris142

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The only way to accurately charge the system is by weight, meaning use refrigerant scales. The pressures should really only be used to ensure the system is flowing/cooling properly. I bought a scale for around $120. Extremely sensitive and great for weighing other things for weight balancing etc.

I have bought oring sets from both Autozone and Oreilly. But an a/c compressor shop will have the best quality. They usually give you about 200 assorted. Whereas the auto shop gives you about 25. I've done 4 vehicles with my set from the compressor shop and I still have some left.

I was told when you charge that you should account for 1oz loss per can, and 1oz loss per charge from manifold and hoses. This is why the scales are so helpful. You know exactly(minus manifold loss) what's going in.

The nice thing about that pressure switch on the drier is that it has a schrader valve under it. You can remove it while the system is charged and replace the ring.
Yes a scale is ideal.but if you do not know the charge amount my 2.0-2.2 ambient works well
 

79jasper

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I mean the switch was leaking to the inside, where the plug goes in, or where the metal case is crimped onto the plastic.
Kinda like how the filter restriction sensor leaks.

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79jasper

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Here's where it's sitting right now. This is after vacuuming and the 3 12 Oz cans.
Slight frost forming on the vacuum line coming out of the compressor.
Should I call it good? Or add a little more?
It's roughly 80°F right now.
Vent temp is fairly cold. No thermometer.

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chris142

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Is it factory AC? If so it needs 80-85% of the r12 charge if using r134a.what's your r12 charge supposed to be?
 

tbrumm

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I always "thought" 94 was the changeover year for the trucks so I expected that Jasper "should" already have R134a in his truck. Thanks for confirming that Jasper-just means my memory isn't totally shotLOL
 
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chris142

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Then put in what the correct charge amount is.should be a sticker somewhere. 94 was the change over year. I just had a 94 Dodge van in my shop built 9/93 that was still r12
 

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