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AIR CONDITIONING QUANDRY

T

tugalo

NAXJA Forum User
Location
easley, sc
Does anyone know why there are two back-to-back check valves in the adapter that connects the low pressure line to the filter drier? Also, does anyone know how much R134 it takes to charge a 90 XJ?
thanks......
 
You mean this thing? It's some kind of disconnect. It plugs the two lines when you split the fitting.

ac_0029.jpg


The FSM says 36oz of R-12. R-134a usually is about 80% so 30oz should be ok (or 32oz like Sparky). Best to check the low and high side pressures.
 
thats it....my filter drier had two of those fittings to adapt the outlet to the line and each one of them has a check valve in it....never seen two check valves back-to-back. Im thinking of taking the check valves out and just use the open fittings....
 
tugalo said:
thats it....my filter drier had two of those fittings to adapt the outlet to the line and each one of them has a check valve in it....never seen two check valves back-to-back. Im thinking of taking the check valves out and just use the open fittings....
Click to expand...

Can that be done without any harm? I just found a break in one of the valves today. It was the one that the hose connects to. I haven't been able to find it at any local parts stores and don't really want to go to the salvage yard tomorrow.

Will the hose screw directly into the drier without any size adapters?
 
The insides look like this. When the lines are connected and tightened, they butt up against each other and unseat, opening the connection. I thought it was some kind of isolation coupler but you need 2 to isolate the system. I was going to leave hte guts out too but I found o-rings to fit so I put them back in.

ac_0039Small.jpg
 
Saudade said:
The insides look like this. When the lines are connected and tightened, they butt up against each other and unseat, opening the connection. I thought it was some kind of isolation coupler but you need 2 to isolate the system. I was going to leave hte guts out too but I found o-rings to fit so I put them back in.

ac_0039Small.jpg
Click to expand...

The piece I found broken was the fitting on the left (not the spring/valve). What is it called so I can call around and see if I can find a new one?
 
No, you cannot screw the line directly onto the filter drier, the fittings are different sizes.....that's why the adapters are there. The opinion about preventing loss of vacuum and/or coolant if you disconnect the line makes sense.....hadn't thought of that.
Given the fact that R134 is a less efficient coolant than R12, I wonder if flow and cooling would be improved if the check valves were removed from the fittings?
 
They certainly offer some restriction but not as much as the expansion valve (well, that's what it's there for!). Bear in mind my test consisted of using my compressor to blow air through them as I cleaned and flushed them. Personally, I don't see any reason why leaving it out would hurt.

The only thing I can think of in terms of isolation is that the compressor charging ports have isolation valves too. They allow you to service the compressor with minimal refrigerant loss. I suppose, this coupler, used with the compressor valves would allow you to replace either the evap, or the condenser without discharging the whole system. Of course, that was back in the day before venting to the atmosphere was an EPA No No.
 
tugalo said:
Does anyone know why there are two back-to-back check valves in the adapter that connects the low pressure line to the filter drier? Also, does anyone know how much R134 it takes to charge a 90 XJ?
thanks......
Click to expand...

32 oz for the 90 model should be just about right. It held 38 Oz of R-12.

That is not a low pressure line at the filter, it is high pressure!!!!!
I dug into that check valve issue myself. It is safe to remove it, or guy it, many have removed them including me ( I gutted mine). I found out it was an OEM assembly part that allowed part of the AC system to be pre-charged before and during car assembly when the jeeps were built and it is not needed anymore. You can either remove it, or gut it and leave the outer part installed.

The OEM only had one check valve, God only nows how you ended up with 2 of them.

I have been told buy the dealers, and a dozen aftermarket AC guys that they are no longer available. All the pro AC shops either remove them, and install adapter fittings / hoses, or just gut them and reinstall the outer fittings.
 
Ecomike said:
That is not a low pressure line at the filter, it is high pressure!!!!!
Click to expand...

That's correct, musta missed that in the OP.

I found out it was an OEM assembly part that allowed part of the AC system to be pre-charged before and during car assembly when the jeeps were built and it is not needed anymore.
Click to expand...

Ah, makes more sense than my theory.
 
Ecomike said:
32 oz for the 90 model should be just about right. It held 38 Oz of R-12.

That is not a low pressure line at the filter, it is high pressure!!!!!
I dug into that check valve issue myself. It is safe to remove it, or guy it, many have removed them including me ( I gutted mine). I found out it was an OEM assembly part that allowed part of the AC system to be pre-charged before and during car assembly when the jeeps were built and it is not needed anymore. You can either remove it, or gut it and leave the outer part installed.

The OEM only had one check valve, God only nows how you ended up with 2 of them.

I have been told buy the dealers, and a dozen aftermarket AC guys that they are no longer available. All the pro AC shops either remove them, and install adapter fittings / hoses, or just gut them and reinstall the outer fittings.
Click to expand...

I did check with the dealership today and the valve I questioned about has been discontinued, however they did show 32 left in Milwalkee. I am going to get one at Pull a Part Monday and put everything back together.
 
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