AC Expansion Valve Repair and Setting

[ZCurves]

Here are Part Numbers and Sources for modern Evaporators, Expansion Valves and Accum/Driers. Heater Valve repair kit too!!

Remember to order Flared Fittings only. On the Drier you will need to break away the mounting bracket that is included so that you can use the one on your Z.

Use a new Condenser. If you are using R134a, then you might add a electric fan in front to lower the compressor head pressure (Colder AC, Cooler Engine).

Evaporator:

http://www.rwiamerica.com/ShopByVehicle.epc?q=1977-NISSAN/DATSUN---80z-L6--753cc--.8l--F/i--Vin--L--8e&yearid=1977%40%401977&makeid=60%40%40NISSAN%2FDATSUN%40%40B&modelid=12594%40%40280Z&engineid=6557@@L6-2753cc+2%2E8L+F%2FI+Vin+L28E@@6557&catid=6@@Heating

~or~

http://www.thezstore.com/page/TZS/PROD/16-7520

Expansion Valve & Accum/Drier (USE FLARED FITTINGS!!):

http://www.onlineaccompressors.com/addtocart/1982_Nissan/280ZX/A-C_Expansion_Device/60-40201.html

Heater Valve Repair Kit from NAPA:

Part No. BK 6601000

Edited September 7, 2011 by ZCurves

[zeeboost]

I have several cans of freeze 12 so I wasn't planning on converting this one. I appreciate the links to this stuff, but I was fortunate enough to find a local shop that can do custom a/c work (modify my evaporator core for a modern expansion valve) so I'm gonna take it by them tomorrow and see if they can do a quick turnaround. Do you think I'd need to replace the condensor even if the pressure holds up and I'm not converting it to r134a?

[ZCurves]

Yeah, you should be fine as long as it is not leaking. I would flush it real well though. I remember when I was converting mine, that the old refrigerant oil had turned brown and nasty -generally gunked up everything. I would like to see some picks of the Evaporator Core with the modern expansion valve -that would be interesting.

[Outlier]

I got a new four seasons pressure switch (35758) which is supposed to be compatible with their receiver drier (33286). The receiver drier switch port is 1/2" and the pressure switch is 3/8" so that won't work at all.

At this point I figured if I can't seal what I have, then I will need to replace the receiver-drier and pressure switch again, so I bought some metallic epoxy putty and wrapped the joint thoroughly. It is holding for now, but time will tell if it is actually a solution or not. I'll keep you posted.

[hr369]

if the epoxy fails try this stuff it's thick and slimy. you have to specify which refrigerant you're using. these guys in phoenix know their stuff when it comes to auto a/c. they also have a great message board for advice on auto ac.

http://www.ackits.com/c/Nylog/Nylog+O-Ring+Lubrication.html

I got a new four seasons pressure switch (35758) which is supposed to be compatible with their receiver drier (33286). The receiver drier switch port is 1/2" and the pressure switch is 3/8" so that won't work at all.

At this point I figured if I can't seal what I have, then I will need to replace the receiver-drier and pressure switch again, so I bought some metallic epoxy putty and wrapped the joint thoroughly. It is holding for now, but time will tell if it is actually a solution or not. I'll keep you posted.

Edited September 12, 2011 by hr369

[Outlier]

I appreciate the thought. Nylog is the type of thread goop the A/C shop used that didn't hold. The epoxy route was a waste of time as well.

I heard from Four Seasons today and apparently they have an error in their catalog cross reference for the switch port size. They also do not have a low pressure switch with that thread size.

Back to the drawing board.

[hr369]

teflon tape on the old switch

http://www.ehow.com/how_7679602_use-teflon-tape-refrigeration-connection.html

[sblake01]

If you're going to use teflon tape on automotive AC, I'd recommend the yellow teflon rather than the more common white. It's designed for gas line connetions, it's thicker and will withstand higher pressures.

[sblake01]

I appreciate the thought. Nylog is the type of thread goop the A/C shop used that didn't hold. The epoxy route was a waste of time as well.

I heard from Four Seasons today and apparently they have an error in their catalog cross reference for the switch port size. They also do not have a low pressure switch with that thread size.

Back to the drawing board.

You could cap the port on the rec/drier or get one that doesn't have a port and use an inline switch port in the hose.

[ZCurves]

Perhaps you could find a brass fitting that would fit the Drier in which you could thread to fit the Pressure Switch?? Ultimately you could take your old Drier to a parts house and try several different kinds of pressure switches until you made a match, then install in the new Drier. It is important not to open your new Drier until time for install as it will begin to 'accumulate' moisture from the environment. The pressure switch only needs to be two pole.

[zeeboost]

Figured I would go ahead and update my progress with this. The a/c shop (Austin Rebuilders in case anyone is curious) told me my evaporator wouldn't hold pressure, so I had them order a replacement in which I could install a modern expansion valve with. I also had them make me a line with 2 90* bends so I can use a generic universal drier along with a common pressure switch. The evaporator was pretty close to the original size, but I still had to trim the metal on the top of it to get the housing to seal up all the way. I hooked everything up but it still won't hold vacuum (loses 30" in 5 seconds so it's a huge leak somewhere). I haven't replaced the rubber discharge line between the compressor and condensor so I'll replace it tomorrow and go from there. Even if it's not the source of the leak, the peace of mind is worth it.

Zcurves, once again, I appreciate your help with this topic. I have 3 pics of the setup (although they're cell cam pics):

- Comparing the old vs new evaporator / expansion valve. The metal I had to trim is on the left side of the new evaporator in this pic:

- Everything installed (dashboard removed, obviously):

- Closeup of the line I had made for the drier:

I do have a question about the compressor oil. I doubt it'd be good anymore since it's been sitting for so long. Do I need to remove the compressor so I can drain out the old stuff or is there a better way of replacing the oil in it? Or does that oil really not need to be changed?

[zeeboost]

Oh yeah, and as soon as I removed the evaporator I discovered why my airflow was so poor