AC line connector valve question

[-JRW-]

When I bought the 02 2500 the AC worked fine. It has since leaked out all the 'frigerant. I bought a big can and took a low line cap off but the can attachment didn't fit, the fitting was the same style just too big (not totally sure what it's for either). The actual low side connection is right next to the accumulator (receiver/drier). The big connection is about a foot farther on the same line and that's where it's leaking. The valve inside isn't seated. The cap itself keeps it down to a very slow leak.

So,

Anyone know a remedy for fixing this valve without suggesting a new line be installed? A new line would mean having to buy a vacuum pump with the capacity to take the system down to below 28inHg. A new tool? NEVER!!

 

[Capt.Crunch]

When I bought the 02 2500 the AC worked fine. It has since leaked out all the 'frigerant. I bought a big can and took a low line cap off but the can attachment didn't fit, the fitting was the same style just too big (not totally sure what it's for either). The actual low side connection is right next to the accumulator. The big connection is about a foot farther on the same line and that's where it's leaking. The valve inside isn't seated. The cap itself keeps it down to a very slow leak.

So,

Anyone know a remedy for fixing this valve without suggesting a new line be installed? A new line would mean having to buy a vacuum pump with the capacity to take the system down to below 28inHg. A new tool? NEVER!!

I have a special tool for replacing the Schrader valves without draining the system for a house air conditioner, but you're going to have to drain it out to replace the Schrader valve on an automotive system, the valve doesn't cost much, have you tried to tighten the valve with a Schrader valve tool, that could also be the problem.

 

[-JRW-]

Thanks! I was going to say this has R-134a so no Schrader valves, then I looked for the new line and saw that there's a Schrader valve down inside the quick connect? Well I'll be! Never knew that. Never worked on one of these quick connect valves before.

I don't suppose a regular tire Shrader will work? I have boxes of those in different sizes for my tractors.

OK, upon further examination of the rock auto selection it appears the Schrader is a 13/64-36 THD (Still trying to find out what THD means - too much dementia, I probably know what it means but don't recall right now). It appears the inside lower o-ring needs to be removed if a regular valve is used. I could be wrong, but they don't sell the Schrader with that o-ring.

I'm dumb enough to try replacing it without evacuating the system and risking potential frostbite of the fingers BTDT with the old R-22 in residential AC units back when I repaired AC in the military.

My how things have changed in the AC world! The large fitting I was referring to is the high side fitting. But it's the exact same hard line as the low side, just a foot apart ... weird to me! So I must assume that the connection between the two quick connects holds the expansion orifice? Geesh I've forgotten a LOT!

 

[ygmn]

THD = THREAD

so 13/64" OD thread with 36 threads per inch.

 

[-JRW-]

YUP! Dementia. What were we talking about?
The space threw me I suspect since most times the THD is part of the number.

But what about the actual question I proffered? Are regular tire type Schader valves acceptable replacements? or do I need to go to town and buy some specialized type just for AC work?

 

[ygmn]

not sure but would be up to seal material

 

[-JRW-]

It's raining here so I have time. I've been wandering the webz and learning or re-remembering some things long forgotten.

GM offers *one* AC service port valve insert for $10 and change. Yeah, not happening unless it's a proprietary unit. I haven't found anywhere that says it is, but I have found some info on the various sizes of valves distributed around the worlds automotive manufacturers. However, I don't believe much of that is relevant here. On GM vehicles it appears (but not yet confirmed) that the low side and the high side valves are different diameters. For my purposes right now I'm only interested in the low side which appears to be a standard car tire valve size and thread (not from visual confirmation of my own).

The GM valve encountered for $10 each (O'rielly's Auto parts) showed that it's seal was made from Teflon. So far I haven't found out what a regular tire valve seal is made from, but I'm still looking. I am prone to believe that that upper seal (which is the primary seal to the valve body tube) on all valves are made of Teflon simply due to their flat and long shape. It seems to me that producing any other type of material for that type of o-ring wouldn't be feasible simply from a durometer standpoint (the seal would not retain it's shape as well if made out of something else). JMO. The actually movable seal on the center stem is the important one here. No indication anywhere on what it's made of.

Nevertheless, there is a wikipedia (I hate relying on wiki's) about Schrader valves; the history and use of. It relates that all valves are created equal. Of course we know they aren't, but it's a wiki. Regardless, they list applications of hot temps, fluids (including hot oils), sub-zero (antarctic tires and other equipment, and even steam) but most important to me - refrigeration applications (obviously), but what it doesn't cover are the possible sealing characteristics or the functionality of each type of application (are they actually ALL made with the same materials or do some have better or worse materials?) Who knows? I can't seem to find any site that does. Maybe that means there IS NO DIFFERENCE? IDK.

Still looking regardless. It's pretty interesting subject overall.

 

[EXT4ME]

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[ygmn]

yes Newer Vehicles using the 134 type refrigerant have a sdifferent size HIGH & LOW Pressure Test ports with Quick disconnect type connections. Also the LOW is larger size then the HIgh Pressure side to ensure no confusion. This is an indutry standard; So fords BMW etc all have the same test port sizes.