Confused about r134 connections

88911coupe · 07-31-2015, 07:40 AM

As part of my ac system revamp I have considered changing the compressor connections to the "quick release" r134 type. I have the Red/Blue quick connects that will go onto my gauge lines but I'm baffled about how to change the ports on my compressor. I purchased a generic kit from the LAPS but can't figure out how to use it. I have a pic and includes one of the schrader valves from the compressor. It will thread into the tall/thinner connector but the plunger in the connector does not reach far enough down to open the schrader valve on the one from the compressor. I have connections to just use the old connectors but it would be nice to have the new easy connections.

tirwin · tirwin's Garage

I just went through this the other day.

The FLAPS (ok, my LAPS was friendly) had about 5 different choices on the adapters. Very confusing to know which ones I needed. In the end I realized that Charlie Griffith had supplied me with the correct ones and I had briefly hid them from myself.

Some of the adapters just screw on. I think the tall silver one on the left is an example. The guick connect engages the Schrader valve in the existing R12 connection.

Other adapters have a Schrader valve that sits in between the R12 fitting and the quick connect. The quick connect pushes in the Schrader in the adapter and it, in turn, pushes in the Schrader valve in the R12 fitting.

The third type of adapter requires that you use a Schrader valve puller to remove the Schrader in the R12 fitting and it's functionality it replaced by the Schrader in the adapter.

To make sure you have it working correctly you disconnect a hose from the gauge and disconnect the R12 fitting with the adapter from the compressor. With the quick connect engaged into the Schrader blow air through hose and make sure you can feel it on the other end. If not, you have done something wrong.

88911coupe · 07-31-2015, 09:19 AM

Thanks Tirwin, yes, the taller one on the left near the compressor schrader valve does screw onto the old valve. However in my case it does not quite touch the valve's actuator to press it in so that has be a bit baffled. The other 3 (2 of which are identical) don't connect up to anything so far as I can tell so I most likely bought the wrong kit. This is not a huge problem since I can still use the old fittings as I've been doing all along.
Thanks

wwest · wwest's Garage

You should only use the type that have you remove and discard the old valves.

DaveMcKenz · 07-31-2015, 09:56 AM

Quote:

Originally Posted by wwest

you should only use the type that have you remove and discard the old valves.

+1

88911coupe · 07-31-2015, 10:29 AM

Thanks, I have looked on Pelican, amazon, etc and can't seem to find those. That's actually what I was looking for but maybe I'm using the wrong term...?

wwest · wwest's Garage

You need to know, measure, the r-12 fitting size.

Nostalgic AC - R134a Charging Ports - Fittings & Hose Kits

wwest · wwest's Garage

Worth consideration..

Nostalgic AC - Binary Switch w/ R-134a Discharge Port 7/16" - AC Pressure Switch - Oil, System Flush & Switches

But I would suggest tossing the included pressure switch, 398 PSI compressor cut-off is definitely a bit high for our ancient systems, especially if you keep the non-barrier hoses (recommended).

I recommend a Red Dot 71R7500, much safer, more conservative, 325 PSI compressor cut-off. Also has the 3rd element for controlling fans or louvers if the conversion to R-134a forces you to go that route.

Amazon.com: Red Dot Trinary Pressure Switch - Generation II 71R7500: Automotive

88911coupe · 07-31-2015, 11:54 AM

Thank! I definitely have a pressure switch on my shopping list.

wwest · wwest's Garage

lamcmick · 07-31-2015, 05:35 PM

There is (2) basic retrofit fittings you need. A low side fitting (blue cap and smaller) and a high side fitting (red cap and larger of the 2). If you can find them use steel fittings. They just screw on the old r12 fittings. They also come with schrader cores in them.

Before you charge the system with R134a you must vacuum the system down for about 15 to 30 minutes. It should hold a vacuum 5 minutes checking for leaks.

Start off with about 70% of the original charge R12.

stormcrow · stormcrow's Garage

Bucl.

Those are schrader valve adapters that you need. Autozone or Advanced Auto sales sells them. The female thread screws onto the schrader valve and then you snap on the quick connect over it. Some of the kits have only two adapters while others may have three.

It appears the ones you have are of a different type and it looks like the female fittings are air adapters. What you need is a r-134-a to r-12 adapter.

88911coupe · 07-31-2015, 07:56 PM

Stormcrow, what you describe is what I'm picturing....and assume can't be that hard to find here in Dallas. Just to clarify, I have totally replaced all hoses and cleaned all then old condensers. My only issue now is exactly what amount of oil (esther) to put back in and where it needs to go. Not sure if it can all go into the compressor or do I need to "spread it around" in other parts like the condensers.
Thanks.