R134a port caps

billr

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I put the pictures with this thread. Those are simple brass "cups" with an M8 x 1.0 screw threaded in and soft-soldered. Loctite would probably work OK, too, but I trust solder better. I tapped the caps with common 5/16"-24, that is so close to M8 x 1.0 that it doesn't matter that, especially since there only a few threads in the cap. The center screw is the same for both high/low, but the cap ID (and O-ring) is not. No "one size fits all" if you want to be sure they seal...

Could I have cut off the screw head and made them prettier? Sure, but that protruding screw makes a nice handle for installing/tightening!

PS: I meant to post this yesterday but must have pushed a wrong button!
IMG_2985.JPGIMG_2988.JPG
 

nickb2

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Spot on work bill, and yes, keep the bolt head, it just makes sense. Nice pics, and nice workmanship.
 

NickD

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Back then, nobody in the US heard of the metric system of units and some weird thread sizes were used, but spark plugs of today are more standard metric sizes. Would have to dig back to my notes to give you those weird sizes. But even today in particular for spark plug and lug nuts hex sizes, are still using the English system of measurements.

Practically all imports whose country is metric, use even numbered metric sizes, When the US converted, first time we used old sizes. Metric increments are small not easy to tell the difference between a 14 and 15 mm bolt head.

So you used an R-134a to R-12 adapter, as soon as you showed a photo, recognized that, have some, but never thought about converting into a cap. But that larger cap is for the much lower pressure low side. Most important is the high side small cap.

Got bored trying to find metal R-134a port caps, wonder if there is a market for them, but seem to be short of a plant now, somewhere in China no thanks to the last 30 years of leadership.
 

billr

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No R12 pieces used. Just standard screws and some brass.

The cap in the pictures is the smaller one, on the low side. The high side has the larger one, which aggravates difficulty in trying to seal it with a plastic cap. Yes, of course I made a cap for the high too.
 

MrConspark

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Would something like these work for you bill, link is for a pair of what seems stainless and probably local north america

Wow that site has a great range of fittings for all purposes.
Um just a thought Billr, you may need to change the shraeder valves in the access ports, the caps are only dust caps, hence why they are made of plastic with a seal inside. In my experience they don't always keep the dust out either. 9/10 leaks I've found are from the caps being loose or missing, so your idea of a better metal type one would be good, but adding the valve change would be an added bonus I reckon.
 

billr

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Yeah, I changed the valve stems; but that had already been done fairly recently once before. I wanted the caps for a certain back-up.
 

MrConspark

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Yeah, I changed the valve stems; but that had already been done fairly recently once before. I wanted the caps for a certain back-up.
I'm hearing you Bill, have seen the plastic ones break off from being overtightened as well.
 
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