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So putting back together the evaporator box interior unit I received disassembled. And I have a few questions in the event someone knows the answers to this rare bird:
  • Heater valve: no big surprise here; it's broken. Plastic broke at the inlet neck (see pic below). I am guessing this it not repairable, though 21st century adhesives surprise me sometimes. If someone has a repair suggestion, let me know.
    • But assuming it is not repairable, what is the alternate heater valve option? I know Alfettas/GTV6s can use a Jag XKE heater valve. This GTV valve looks to be the same one as an Alfetta/GTV6. Or can I just use a standard 105 one?
    • And how much does the the copper thermocouple probe for the A/C matter? Guessing if I run the fan full bore to clear the moisture for prevent coil freezing, won't matter not having it.
  • "Bulkhead" - the part shown in pic below. What is it? Just a flat piece of thin plastic? What does it do?
  • "Gasket" at top of box - part shown in pic below. Is this just essentially foam weatherstripping type material?
1681119
 

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Hi there,

Heater valve: Those old heater valves are quite brittle and finding an NOS one will likely be just as brittle and brake - the plastic on these valves seems to deteriorated over the decades. This is how I solved the problem on my Borletti box.


In terms of the temperature probe for the heater tap - I never quite understood how this was supposed to work - and I managed without one for 7 years without incident.

Gasket: Basically correct, Some kind of weather stripping or rubber. I would say 3/4 of an inch thick. When I originally pulled the box apart it was weather stripping but I used rubber because it didn't compress much and because it lowered the box slightly giving me more clearance room for the cowl drain tube.

Bulkhead: This part is rather strange isnt it. definatley keep it if you can or replace it with a stiff piece of plastic with the same sort of cuts at the front. Presumable this has to do with drainage of water from the evaporator.

This thread covers a lot of issues you will be dealing with:


HTH - Goodluck
 

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Discussion Starter #3
@WA-Alfa - your thread(s) remains permanently up in my browser! It's my cookbook for all of this. I just somehow missed your picture of the top gasket, so thanks for directing me.

As I was re-reading through your thread tonight I noticed that my plan for using the original condenser may not be optimal, or maybe not even possible. This is my first run at A/C.

Did you not use the original condenser because: a) you didn't have one, b) it couldn't run R134a c) just wasn't going to provide enough cooling?

Thanks for the reply and sharing your experience!
 

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Hi there,

I'm pleased my thread is of use to someone :)

I assume this is all for your 105 GTV?

I didnt have an original condenser at the time of my installation although from what I have heared from some people it was adequate to the task whenused with the old york compressor. R134a should run in the old condenser just fine just so long as a suitable expansion valve is fitted to the evaporator - I think. The newer after market condensers use a better fin design and so should provide better cooling. My car cooled just fine with the parallel flow condenser but I am planning on sourcing an original condenser and will experiment with connecting it in series to a new parallel flow condenser and then placing them front-to-back. Condenser size is probably the most important part of any AC installation - you want the biggest you can get for that very small space.

You have six options as I see them:

1. Use the original tube and fin condenser which will be ok but probably not fantastic;
2. Use the new style parallel flow condenser which will probably be better than ok but less than fantastic on really hot days and the system may struggle to hold the pressure;
3. Connect two new parallel flow condensers in series;
4. Connect the original tube and fin condenser to a new parallel flow condenser, again in series, and try something no one has done before.
5. Sell me your original tube and fin 105 GTV condenser and try option 2 or 3 ;)
6. Cut out some metal and install a bigger condenser.

Let me know how you go - I'll do whatever I can to help.
 

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Discussion Starter #5
Yep - 74 USA GTV. I am surprised that you haven't been able to find an original condenser, unless it is a unique size for GTV. You may have to ship from US, but imagine there is one out there somewhere...Larry at APE probably for sure.

Meant to ask you on the heater valve...since you put it at the end of an extension hose, how/where did you mount the valve to the Borletti box or dash so that it would stay in place when you actuated the heater control cable?
 

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Hi there,

I found some photos for you.

Here is the bulkhead:

1681424


1681423


I remember now that I had two evaporators. I hacksawed off on end of the copper pipe where it connects to the heater tap and used it as a connector. In the photo shown below it is routed behind the box but this may or may not fit - I may have routed it forward so the heater hose goes over the top of the box.

1681422


For th heater tap I basically just made something up. I have some very poor quality photos below which I will share. I used stuff from the shelf section of the local hardware store.

1681421



The heater tap is metal and comes from an earlier model 105. It's available from most suppliers including classicalfa


1681418



I also found an image of the weather stripping below.

1681420
 

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Discussion Starter #7
Forgot to thank you - this is SUPER helpful. Just dawned on me, I should be taking some pics and posting to help the next person since info on this topic is pretty limited. So I'll start doing that.
 

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Just dawned on me, I should be taking some pics and posting to help the next person since info on this topic is pretty limited. So I'll start doing that.
I approve of this message.

LOL
 

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@horsewidower is running for office. ;-)

So looking at that "bulkhead" thing at the bottom of the Borletti unit (which my unit is missing), it seems that it is a foam like material. Seems maybe its purpose is to absorb moisture so that it can slowly drain from the box vs. not having it and having moisture exiting much faster from the Borletti box?

Not sure. Either way, I guess I'll make one.
 
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From what I recall it was definatley not a foam or foam like material. I also caution aginst using any substance in the bottom of the evaporator that holds water due to the risk of Legionnaires' disease. From my memory the 'bulkhead' as you put it is more like a stiff plastic sheet about 2-3mm thick.

You may also notice what appears to be extremely old glue around the edges.
 

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Discussion Starter #11
Ah ok. Looked like a foam hvac filter material in your pictures. If it’s a solid plastic, then I am really stumped as to what purpose it served.
 

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@Jim G - OK, that was an oversight. I didn't even crosscheck the part numbers. Turns out both the A/C box and standard heater box take the same seal you note above - 105.48.57.229.00.

Thanks for that Jim...much appreciated.
 
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