found an a/c leak - not sure how to fix it - '95 RMW

Recharged the system and using a leak detector, I got a strong hit on the fitting/connection by the firewall (right side as you look at it from the front of the motor)

There's a 13mm nut on that fitting. When I take that nut off, what am I going to deal with? What's behind that? Is it just an O-ring sealing the connection there?

Thanks

There's an O-ring on each one. Pickup the variety pack at autozone, make sure you get the green ones for AC systems.

95BRMW wrote:

There's an O-ring on each one.  Pickup the variety pack at autozone, make sure you get the green ones for AC systems.

Ok, thanks. I was able to find a diagram- my lack of knowledge of the terminology made it hard to find. I found another very obvious leak coming out of the high side test port valve. I'm not sure if the valve can be replaced, it's not entirely clear if it's threaded into the pipe or if it's permanently installed. If anyone knows for sure, I'd appreciate it.

Looks can be deceiving- it does indeed appear to be threaded into the line. Looks like it'll be an easy fix once I get the parts and a vacuum pump.

It should be a Schrader valve, but I do not know if it is replaceable. If it is, you have to get one that is designed for refrigerant. The junk yard can supply the part. You may even be able to get the entire part with the Schrader valve in it from the junk yard. All of the 94-96 B-body AC parts are the same. If it is not replaceable, you can get the part from Rock Auto.

Check this guy out on ISSF: http://www.impalassforum.com/vBulletin/showthread.php?t=349706

GM didn’t use a Schrader valve on the high side – they used a stemless flat rubber check valve fitting with 8 flats so a standard socket won’t fit. You have to use a wrench or a special socket to replace it. When unscrewing the old port, make sure you use a wrench to hold the line fitting or you could bend, fold or mutilate your high pressure line.

Replace it with AC Delco part number 15-30418 (which comes with a cap) or 15-5438 (port only, no cap).

Thanks, got the parts on order. And now the radiator just started leaking... timely.

As said before, the low side is the only regular Schrader valve. I bought a bag of AC spec'd Shrader brand valves off ebay fairly cheap. If anyone is working on their AC and is replacing the accumulator, replace the valves with good ones, the valves they ship with are junk, I've had 2 leak right out of the box.

Just wanted to follow up on this- picked up a HF vacuum pump and finally got around to replacing the accumulator, high side test port, orifice tube and just about all the O-rings. Everything is working properly according to the FSM. I did notice quite a lot of small aluminum bits on the orifice tube- not sure what that was all about.

lamune wrote:

I did notice quite a lot of small aluminum bits on the orifice tube- not sure what that was all about.

Sadly, those bits are likely guts from your compressor. The #1 cause of compressor failure is lack of lubrication. I STRONGLY suggest you get some AC oil analyzers and check the oil quantity/quality ASAP.

Brands include "Pitt Stop", "Red Tek" and "Meister". Here's some examples:
http://www.aliexpress.com/item/NEW-10-PCS-R134A-automotive-air-conditioning-oil-detection-cotton/1325093966.html
http://www.redtek.ca/win_oilanalyzer.html

They are a simple cotton filter inside a clear plastic housing. You run the AC for a few minutes to mix the oil in the refrigerant and then, with the AC compressor running, briefly push one of these over the LP port 3 or 4 times. It's not an exact measurement, but if the cotton is not immediately pretty well coated in oil then you need to add some. They will also give you an idea of any contamination. In my experience, the difference between barely wetting the end of the cotton with oil and a good soaking is about 1-1/2 ounces of oil.

You can add oil either by recovering the charge and pouring oil in, or by use of an oil injector. Some injectors are an accessory for a recovery machine, using the flow of refrigerant through the device to carry the fresh oil into the system, some are stand-alone and rely on mechanical pressure like a crank or lever. I would avoid the simple plunger style (eg: Interdynamics). They are OK for use on an empty system before charging, but in this case you have to force the oil in against the AC system pressure so you would need a very strong thumb.

Finally, I would plan on replacing the orifice tube a few times over the next year or two to monitor things.

Thanks Buickwagon- I may just do that. I would suspect with several people attempting to fix this thing with "A/C PRO FIXIT IN A CAN!" type stuff, there's probably more oil in there than necessary. Having some data, like that test, seems like a prudent idea, as well as changing the orifice tube to catch any more metal bits that may be floating around in there.

The "injector" type thing might work if you use it on the low side with the compressor running since you're only overcoming something like 30 PSI there. One of those little "oil shot" cans may work too, or I can just wait until I change the orifice tube next and shoot some in there if the cotton test fails.

Thanks for all the help, this is a great forum. I never did A/C work like this and it feels great to learn something new and fix something that was broken.