Classic auto air questions

[Pete in NH]

That's the stuff, plain old R-134A. That looks like a very decent price also! Does that gauge set include a can tap? Most don't but you never know. You might have to get one separately.

Yes, the sealer stuff is very popular because people are looking for a cheap way out to get their A/C working again. Little do they know that if they use the silicate type sealer they can potentially destroy their entire A/C system and cost themselves thousands of $ in repairs.

[Dino]

I am unsure if the gauges come with a can tap.  I'm picking it up today.  I'll have all the A/C parts by Saturday so I'll be able to assemble the system, but the car is far from firing up so charging will have to wait a bit.

I was calibrating my gauges yesterday and I can't get my fuel gauge to read right, plus the needle on two are damaged so that's going to be a bit of a delay.

[Dino]

Got it all done!  I bought 32 oz of pag oil and used half to flush the compressor.  Better safe than sorry!  I filled it up with ~8.5 oz and assembled the hoses.  Stuck it in place and hooked it all up, drier last.  Everything went together smoothly.  I used Nylog on all threads and O-rings, that stuff is pretty amazing!

I mounted the adjustable thermostat switch where the balance resistor used to be so I have good access in case I need to adjust it, and so it's close to the evaporator tubes.  The low pressure switch is on the back of the drier which worked out nicely to route the electrical. 

This pic shows the first time in who knows how long the car has heater and A/C hoses again.  It's still an ugly black engine bay, but at least it has a few things going for it now.

The long blue wire is the AC wire that needs to be cut and connected to the compressor, but I'm fresh out of connectors so I need to go shopping.  Nothing fancy here, a bullet type maybe.

I spun the compressor about twenty times o circulate the oil.  I won't be able to start the car for a while so when the time comes and I vacuum the system, would I not lose any of the oil?

[ODZKing]

Nice job Troy.     You did better than me, I had to call for help!!!

There's nothing wrong with mounting the compressor on the side like your photo shows, you just want to get it on without dumping oil out of a port.

That is actually the way they suggest mounting it in the instructions for Big Block.  Small block is on top.

[Pete in NH]

Nice job, Dino! You're getting really close to some cold air!

The oil will stay in the system when you vacuum it out, no need to worry. When you get close to charging it up, let me know and I'll type out the charging details.

[Dino]

Thanks Pete!  Will do!

[will]

Can you rotate the fittings on the back of the compresor? It looks like the fittings are clockable. 5 bolts, I'm thinking you can rotate the fitting block a bolt hole over and it would work, I'm just not willing to void the warranty or dump oil all over the top of my engine.

[Pete in NH]

Will,

I think the short answer is, yes because Sanden offers different port positions as an option. That being said, I would not try it. For sure not mounted on the engine. I would think you would want the compressor off the car and standing on its hub or you will have oil all over the place.  Also, the valve plate is right under that port head and I suspect it too would have to rotate in some fashion but, that would be a question for Sanden or someone that knows more about those compressors than I do. There are also gaskets under the port head and valve plate that would have to be replaced, most of the time they are one time use metal crush types. You would also want the torque specs. for those bolts. Like I said, I wouldn't try it without some further research.

[Pete in NH]

Dino,

I was just look at the picture of the finished installation again and noticed two things. The first is it looks like you are using the old R-12 serpentine condenser rather than a newer parallel flow type. Those were pretty big condensers so it may not be too big of an issue but, it will not be as efficient as things could be and A/C cooling may suffer under tough conditions with an R-134 system. Second issue is I noticed you don't have a fan shroud. That is going to be critical in moving as much air as possible through that condenser. Between the serpentine condenser and no shroud I think you are going to risk very high compressor discharge pressures under really hot weather conditions. I think you are at least going to want to get a shroud on that radiator/fan set up or add a high pressure cut off switch if things get out of hand pressure wise. I don't think CAA uses a high pressure cut off switch in their systems

[Dino]

Hi Pete,

It is the condenser that came straight from classic auto air so I doubt it is R12.  It looks like the stock condenser but is not identical, I still have my old one.

I do have a shroud but it was not installed until two days ago.  

[will]

Will,

I think the short answer is, yes because Sanden offers different port positions as an option. That being said, I would not try it. For sure not mounted on the engine. I would think you would want the compressor off the car and standing on its hub or you will have oil all over the place.  Also, the valve plate is right under that port head and I suspect it too would have to rotate in some fashion but, that would be a question for Sanden or someone that knows more about those compressors than I do. There are also gaskets under the port head and valve plate that would have to be replaced, most of the time they are one time use metal crush types. You would also want the torque specs. for those bolts. Like I said, I wouldn't try it without some further research.

Thanks for the reply Pete. I decided to rotate the compressor 90* instead of taking the back off. I considered it, but than figured that those gaskets inside were gonna rip or the o-rings would be flat. I'd rather have an exploded view before I jumped in. I saw the chart earlier in the thread, so I went with that option. Now all the under hood stuff as far as a/c is done. On to intake and more fun stuff. Hoping for noise tomorrow.

[Pete in NH]

Hi Dino,


You should be all set with that shroud and it looks like a new fan drive! It was kind of hard to tell about the condenser with only being able to see the very top of it in the photo. But, I wanted to ask since you are getting so close to getting the A/C system working. That fan and shroud will move plenty of air through the condenser.

[Dino]

Thanks Pete, I appreciate you looking out for me.   

The fan and clutch are pretty new.  I installed them last year so I put maybe 1000 miles on it, if that.  The shroud has never been on, my car didn't have one.  The radiator is out of a C body so when I found a cheap shroud on ebay for one of those I jumped on it.   

[Dino]

Alright I guess I have done enough testing the car and since everything seems to work I guess it's time to charge the A/C!

I bookmarked a site somewhere on how to do this but any tips anyone may have are welcome.  I have the A/C manifold kit, 3 cans of r134a and a can tap.  And I have a loaner vacuum pump from Autozone.

[Pete in NH]

There are two service ports in the system, a suction port and a discharge port. The suction port will be somewhere in the line between the evaporator and compressor. This will be the line that does not have the expansion valve connected to it coming off the evaporator. The discharge line will be the line running directly from the compressor to the condenser in front or the radiator.

The gauge set as you look at the front will have a high pressure gauge on the right side (discharge pressure) and a lower pressure/vacuum gauge on the left side (suction pressure). There will be two side wheel valves on each side of a three port manifold. The ports directly under each gauge are connected to the respective gauge above. The center port of the manifold can be connected to either or both sides and gauges by opening their respective side valves.

I would repeat turning the inner compressor hub 20 turns to again make sure there in no oil in the compressor cylinders or valves and remove the caps from the suction and discharge service ports.

To connect the gauge set to the car A/C system- Connect the RED hose to the gauge discharge pressure port (right side) and the other end of the RED hose to the discharge service port on the car. Connect the Yellow hose to the center manifold fitting and the other end to your vacuum pump port (some older pumps may need an adaptor fitting). Finally, connect the Blue hose to the gauge suction pressure port (left side) and the other end of the Blue hose to the suction service port on the car. At this point make sure both side wheel valves on the gauge set are closed (all the way in).

Start the vacuum pump and then slowly open both side wheel valves. The left side gauge should slowly start to swing down and register vacuum. Within 5 minutes or so you should be registering well below 20 inches of vacuum. If not, there is a leak somewhere and you will need to stop and find it. If the left side gauge goes down immediately into deep vacuum, it is likely the gauge hose couplers did not depress the service port valves. The suction side gauge should get down between 29 and 29.5 inches of vacuum. At this point you can let the vacuum pump run for as long as you want but, I would let it run at least 30 to 45 minutes. I like to let it run at least two hours to pull out as much water vapor as possible.

When you decide the vacuum pump has run long enough, close both side wheel valves tightly and then turn of the vacuum pump. At this point you will not open the discharge side wheel valve again and will work only with the suction side valve. Now you will let the system sit under vacuum and see if it will hold the vacuum over time. I let mine sit over night but, I would let it sit at least a few hours. The vacuum reading should not change except for very, very small changes due to ambient temperature changes.

If the system has held its vacuum well you are ready to charge it with R-134. Take your R-134 can tap and turn the top T handle or valve all the way out (counterclockwise). Now thread the can tap onto the top of the R-134 can and then remove the yellow hose end from the vacuum pump and attach it to the can tap fitting. Now run the can tap valve back in (clockwise) to puncture the seal on the top of the R-134 can and then run it back out counterclockwise to allow R-134 into the yellow hose. Loosen the manifold end of the yellow hose to allow the R-134 to purge the air out of the yellow hose and then re-tighten the hose fitting on the manifold.

Now turn the car's ignition switch to the on run position but do not start the engine. And turn the A/C on. Set it to Max. Air or recirculate with the blower on high with the car's windows down. Now, slowly open the suction side wheel valve on the gauge set to let the system vacuum draw in the R-134. At some point the R-134 will pressurize the system to the point of allowing the low pressure cut-off switch on the receiver /drier to close and the compressor clutch should pull in. You now have enough R-134 in the system to carry oil around and lubricate the compressor. If it is a cool day you may have to help the R-134 out of the can by setting it in a pan of warm water not over 120 degrees. You should be seeing 50 to 60 pounds of static pressure on the gauges. Close the suction side wheel valve and start the car's engine. The compressor hub should be spinning and you can start to slowly re-open the suction side wheel valve and pull in the remaining R-134 in the can.
At some point the can will be empty. Close the suction side wheel valve, remove the yellow hose from the can tap and repeat the procedure for attaching the can tap to the second R-134 can and purging the yellow hose. With the hose purged, slowly open the suction side wheel vale and pull in the second can of R-134. CAA calls for 24 ounces of R-134 in their systems and you should be there with two cans. At this point close the suction side wheel valve again. The suction side gauge should be reading some where between 22 and 28 pounds of positive pressure and the discharge gauge should be over 150 pounds perhaps as high as 275 pounds or a bit higher depending on ambient temperatures and air flow through the condenser. You should be making cold air inside the car.  The discharge line off the compressor will be too hot to touch and the suction side line on the evaporator should be cold.

Classic Air says your system holds 24 oz. of R-134, that's two cans. You may have to add a few Oz's from a third can to make up for refrigerant trapped in the gauge set hoses.

If things look good, turn off the A/C system and engine. Disconnect the gauge set hoses from the system service ports and replace the caps on the service ports. YOU ARE DONE!

The EPA would like you to have an under hood label stating the type and amount of refrigerant in the system as well as the type and amount of oil used. This is very useful to anyone servicing the system in the future as well as yourself a few years down the road when you forget exactly what you did!

[Dino]

Pete you rock!   

I will follow your instructions to a T and get this done!   

Very good idea on the label, I would probably not remember what oil I used a year from now.   

[Dino]

If the left side gauge goes down immediately into deep vacuum, it is likely the gauge hose couplers did not depress the service port valves. The suction side gauge should get down between 29 and 29.5 inches of vacuum. At this point you can let the vacuum pump run for as long as you want but, I would let it run at least 30 to 45 minutes. I like to let it run at least two hours to pull out as much water vapor as possible.

Hi Pete,

The left gauge goes down to almost 30 as soon as I open the valve at the line, so before I even open the manifold gauge knob.  I reinstalled the pressure couplers a few times but don't see anything wrong with them.  The pump is currently running and showing just shy of 30mmhg vacuum.

Is this okay or no?

[Dino]

I shut the pump off quite a while ago and the needle reads about 30mmhg. 

[Pete in NH]

Hi Dino,

It sounds like the gauge set hose couplers are not opening the service valve ports. When you're pulling a vacuum you can slowly open both the left and right side valves on the gauge set. I say slowly, because as you do you will hear the vacuum pump change its sound as it tries to catch up with larger volume of air in the A/C system.The pump will sound sort of like a gurgling sound as it gets hit with the air. If you don't hear that, the pump is just pulling down the gauge set hoses and not the entire system.

Do the gauge set instructions say anything about what to do if the coupler does not open the service port? My R-134 gauge set is a Robinaire and I've never encountered that problem.

[Pete in NH]

Dino,

I just had another thought. My Robinaire set couplers snap in place over the service port but then you have to turn a small wheel on top of the coupler to open the service port valve. Perhaps your couplers are the same and you didn't open the valve on top of the coupler. This was done to prevent discharging refrigerant to the atmosphere from what is trapped in the hoses, it's an EPA thing.

If your couplers are different post  a picture of them.

[Dino]

Hi Pete,

The couplers do have a wheel that needs to be closed and opened but I followed your instructions along with the one that came with the manifold kit.  I will try again today and see what it does.  The gauge still reads around 30mmhg but it got there almost immediately.  The compressor sound did change when I opened the manifold valves.

[Pete in NH]

If the pump sound changed as you opened the valve you might be okay. If the pump is a large one it may pull the system down fairly quickly. My small Robinaire pump has to work on it a few minutes and you can see the gauge swing down slowly but steadily.

One way you will know for sure is if the R-134 goes in or not. If it held vacuum over night and you did have the whole system pumped down, you're in good shape- no leaks!

[Dino]

That may sound too good to be true; the pump is a 1.8 cfm model from the OEM brand and the gauge was at 30 in little to no time. 

I will hook up a can and see what it does.  Will it show on the gauges if it is charging?

[Dino]

I have the first can hooked up, when I slowly opened the blue manifold valve, pressure went up to 50, came back down to 20 fairly quickly, and is now slowly rising.  It's at 26 psi at the moment after about 5 minutes charging.  Should I wait with this can until pressure builds up or hook up the second can to increase pressure?

Also, I don't start the car until pressure is up and the compressor kicks in?

Edit:  It was up to 30 as soon as I posted this.

[Dino]

Okay the pressure just went past 40, I think it's looking good!  Man I can't wait to have functioning A/C in this car!