A/C tech 101...

[Guest 73Turbo240z]

Alright so i have recently acquired a cherry condition 78' 280z to be my daily, virtually no rust what so ever, fresh paint, etc.. just a super nice car.

 

downside is that the previous owner took out the AC compressor cause he says he blew a high side line refilling it one time... seems odd to me that he'd pull it, either way though basically i want my 78' to have AC, houstons a big enough sauna that i'm breaking down and doing it.

 

I don't know anything about AC systems, i've searched here, mostly posts about 73' factory retrofits and whatnot. This 78' was a factory AC'd car, i have the compressor, i looked through MSA and VB, niether offered lines, so where can i acquire a new high side line? and does anyone know of a good online write up on how to recharge your AC system, i figure it's obviously fully drained since the compressors gone currently. So if i can read up on how to recharge it properly, that would save me getting raped by houston AC shops.

[randy 77zt]

a/c work is tough at home becuase most people dont have the proper tools (evac pump.manfold gauges) to recharge the system.if you need a system you can piece one together from junk yard parts.75-78 z's used same parts.hoses can be repaired by cutting the crips off and crimping new hose on.mmany radiator shops can make custom a/c hoses.if you switch to r134(new stuff) you have to flush the old oil out of the system and should have a new reciever/dryer installed.the r12 compressor oil soildifies with r134.my 77 had a leaky evaporator core when i bought it.i found a car holding a charge at pick&pull(before treehugger laws on r12) and discharged the system and removed my part.your best bet would be to get the system installed at home and have a shop evac and charge it.but if you have a leak you will have to do this over & over till you find the leak.last i heard r12 is $100 a can.nissan still stocks some parts like pressure switches and prices arent bad.

[spotfitz]

Funny thing you mention this. I tried charging my system about 2 months ago and blew the high side line. I just had a high side line made for my '77 yesterday. I had it done at an a/c parts house. Look for one in the phone book. Cost: $15+tax and they cut it to length and crimped it right in front of me. If it will help, what they told me was, it is standard #8 line and the ends are just simple crimp on 90*. The fitting going to the condenser is actually about a 100*, but will easily fit. Just take the hose down with you since the fittings sit at a 90* angle to each other and the bend in the line is hard to measure.

Hope it helps

[Guest 73Turbo240z]

I've got the gauges, at least i'm assuming the gauges are the same that you can buy @ your average autoparts store, i don't have a vacuum pump for evac however.

 

The previous owner trashed the line when it blew according to him... so i guess i'll have to try and find one in a junkyard to base off of.

[strotter]

There are inexpensive (albeit annoyingly noisy) little "impeller" pumps available at cheapo tool stores - around here (central Cali) we have "Harbor Freight" stores. Sometimes a useful place to pick up something you'll only use once or twice. Anyway, these pumps hook up to your compressor which spins an impeller which in turn pumps down your system. Create a good vacuum, too. Cheap.

 

Here's one for '134,

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92475

 

and there's another one for R-12, but it's not coming up on the search. I'm sure you have similar stores in your area.

 

Really all you'll do is seal up your system, pump it down for half an hour (to boil out all the water vapor), pull off the gear and let it sit overnight w/o pressure loss (checking for leaks), then in the morning (if all went well) go about charging it up. While charging, of course, you make use of your pressure gauges per your cars shop manual - which you'll need, because you need to know how much refrigerant, what pressures to look for under what conditions, so on. There are a number of sites on the 'web which detail the procedure in general terms.

[Guest 73Turbo240z]

There are inexpensive (albeit annoyingly noisy) little "impeller" pumps available at cheapo tool stores - around here (central Cali) we have "Harbor Freight" stores. Sometimes a useful place to pick up something you'll only use once or twice. Anyway' date=' these pumps hook up to your compressor which spins an impeller which in turn pumps down your system. Create a good vacuum, too. Cheap.

 

Here's one for '134,

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92475

 

and there's another one for R-12, but it's not coming up on the search. I'm sure you have similar stores in your area.

 

Really all you'll do is seal up your system, pump it down for half an hour (to boil out all the water vapor), pull off the gear and let it sit overnight w/o pressure loss (checking for leaks), then in the morning (if all went well) go about charging it up. While charging, of course, you make use of your pressure gauges per your cars shop manual - which you'll need, because you need to know how much refrigerant, what pressures to look for under what conditions, so on. There are a number of sites on the 'web which detail the procedure in general terms.[/quote']

 

we have HF's here in houston as well, i only have FSM's for 73' and 83' so i guess i'll need to scour the net to find out what a 78's capacity is, i wouldn't even know off hand if parts were missing since i'm such a noob to A/C... this is a good start though.

[80LS1T]

Another thing worth mentioning is that you will find these cans of R134a refrigiant at parts stores that contain "sealer/stop leak". I cant stress it enough that these sealers are not a good idea. Once the sealer comes into contact with air it hardens. Well sure it seams like a great idea.....but what happens when you say blow a line? Guess what, where ever that sealer is in the system at that time...its going to turn hard as rock and now the only real way of fixing your A/C is to replace everything. Not to mention if the shop you take you car to has a "seal identify" system, they will not service your a/c because it will damange their a/c machine.

 

So when buying R134a, just get the plain R134a.

 

 

Guy

[Nismo280zEd]

Not sure what part of houston or spring your located in, but there is a hydraulic/ AC shop off Sawdust just north of spring right before the Woodlands, they would surely have the fittings and probably be able to custom make a new line for you. They mostly do commercial work.

-Ed

[Guest 73Turbo240z]

Not sure what part of houston or spring your located in' date=' but there is a hydraulic/ AC shop off Sawdust just north of spring right before the Woodlands, they would surely have the fittings and probably be able to custom make a new line for you. They mostly do commercial work.

-Ed[/quote']

 

spring, sawdust @ 45 is about 20 mins from me, got a buisness name?

[spotfitz]

I can get you pics of the hose and an exact length from fitting to fitting if you like(of the new and/or old one). The new one is still sitting on the work bench waiting for me to put it on. It was right at a foot long, but the way the hose hooks up it doesn't have to be exact. They can actually crimp one side of the hose and hook it up. Route to the other fitting, cut to length and crimp it on the car with the crimping tool they used for my hose. Let me know if you need anything.

[Guest 73Turbo240z]

I can get you pics of the hose and an exact length from fitting to fitting if you like(of the new and/or old one). The new one is still sitting on the work bench waiting for me to put it on. It was right at a foot long, but the way the hose hooks up it doesn't have to be exact. They can actually crimp one side of the hose and hook it up. Route to the other fitting, cut to length and crimp it on the car with the crimping tool they used for my hose. Let me know if you need anything.

 

yea if you wouldn't mind shooting photos of the hoses, and perhaps the compressor bolted into the engine bay (if theres an acceptable shot of it), since i've never seen the AC installed in this car i'm having to try and figure it out on my own.

[spotfitz]

Check the descriptions in the pics. I should be posting them in order/direction from fire wall to the front and back to the fire wall(clockwise).

http://album.hybridz.org/showphoto.php?photo=3599&cat=500&page=1

http://album.hybridz.org/showphoto.php?photo=3600&cat=500&page=1

http://album.hybridz.org/showphoto.php?photo=3601&cat=500&page=1

http://album.hybridz.org/showphoto.php?photo=3602&cat=500&page=1

http://album.hybridz.org/showphoto.php?photo=3603&cat=500&page=1

http://album.hybridz.org/showphoto.php?photo=3604&cat=500&page=1

http://album.hybridz.org/showphoto.php?photo=3605&cat=500&page=1

These are high res. pics and atleast one you may have to play with the lighting with your favorite pic program, but it should give you an idea. It was getting dark by the time I got home this evening. I will need to drop these pics in the near future and can email them to anyone that needs them once I pull them from the site(for future searches). Just email me!

This is all from my early '77 which should be the same as atleast the '78 and possibly the '75-'76(I'm not positive, but pretty sure). The compressor bracket that I have a pic of(as described) comes from an '81 with crank mounted CAS. All the other brackets I have seen, excluding dealer installs, but including my factory installed early '74 looks very similiar to this one. They all bolt up the same way to the block. Compressors mount up the same way as due the condensors on the late Z models. The driers I've seen changed on the ZX models, but not by much. I have one for pics aswell, if needed. If you have anymore questions about the routing, just ask. If you need more pics of a specific spot I'll do my best to get them. I do have a rebuilt block on a stand if you need me to mock up something for a better view. I probably have two complete a/c systems in the garage using various parts from different makes.

I have been purchasing new parts for my early '74 for some time now and have done alot of research on this subject. I recently took a '96 altima blower fan and mounted it in the fan housing of my '74. It seemed to be about the same difficulty as Pete's LTD fan mod. I'll be using resistors and relays for this setup. I will be posting my results once I get the whole dash back together for testing of the force the fan puts out. Here in Texas we all know how we have to have a/c in the summer time, especially so with black interior.

Again, if you need anything else......

[Guest 73LT1Z]

Check the descriptions in the pics. I should be posting them in order/direction from fire wall to the front and back to the fire wall(clockwise).

 

These are high res. pics and atleast one you may have to play with the lighting with your favorite pic program' date=' but it should give you an idea. It was getting dark by the time I got home this evening. I will need to drop these pics in the near future and can email them to anyone that needs them once I pull them from the site(for future searches). Just email me!

This is all from my early '77 which should be the same as atleast the '78 and possibly the '75-'76(I'm not positive, but pretty sure). The compressor bracket that I have a pic of(as described) comes from an '81 with crank mounted CAS. All the other brackets I have seen, excluding dealer installs, but including my factory installed early '74 looks very similiar to this one. They all bolt up the same way to the block. Compressors mount up the same way as due the condensors on the late Z models. The driers I've seen changed on the ZX models, but not by much. I have one for pics aswell, if needed. If you have anymore questions about the routing, just ask. If you need more pics of a specific spot I'll do my best to get them. I do have a rebuilt block on a stand if you need me to mock up something for a better view. I probably have two complete a/c systems in the garage using various parts from different makes.

I have been purchasing new parts for my early '74 for some time now and have done alot of research on this subject. I recently took a '96 altima blower fan and mounted it in the fan housing of my '74. It seemed to be about the same difficulty as Pete's LTD fan mod. I'll be using resistors and relays for this setup. I will be posting my results once I get the whole dash back together for testing of the force the fan puts out. Here in Texas we all know how we have to have a/c in the summer time, especially so with black interior.

Again, if you need anything else......[/quote']

 

 

Sent you an email- need the sizes of the fittings on the firewwall of a 75 280 w/ factory AC:

 

Question from AC parts supplier-

I need you to give me a measurement of the ID of the threads on the swivel nut, and OD of the male threads on the top fitting.

[Clifton]

I would look for a cheap electric vac pump if you plan to do this often. You can find them on ebay. The cheap venturi ones work but take some time to pull it down. I don't know about 280's but 240's have marginal a/c when over 100* outside. I would also stick with R12. R134 was gone up in price, atleast here. My system only used 2 cans. It cost me less than $20 to use R12 over R134. Look on ebay for it. The more you buy the cheaper it is. Replace the dryer and all schrader valves too.