Howdy there folks. I've been going through my A/C system. I've cleaned up the ac box and vents, resealed the vent flappers, installed a new heater core, new blower motor etc etc.

I had some new lines made up to replace the 30 year old dry rotted specimens. Here's a terrible picture of the one of the new hoses...



Now I'm at the condenser. I would like to run 134a. But I figure like most systems designed for r12, the condenser will be too small. I'm thinking about buying a larger universal condenser to retrofit into place to make up for the loss in efficiency from converting to 134a.

I'll probably get one similar to this.

http://www.ebay.com/itm/like/251422553419?lpid=82

Have any of you done this? I like to see your setup and see how it works. Any and all thoughts are welcome.

Thanks

---Cows---

 

I've been contemplating doing the same thing with my Bronco. I will likely buy the complete kit, something along these lines:

Nostalgic AC - Complete Ford AC Kit - Select an Evaporator - Stock Comp. Mount - Ford AC Kits For Trucks - Ford Complete Kits - Complete A/C Kits

They sell many individual parts, including condensers:

Nostalgic AC - Aftermarket AC Condensers

 

I guess I can't say that I've DONE it, because I haven't figured out how to buy the lines I need to actually run things, but I installed the condenser off of a 2001 Jimmy. It fit ALMOST perfect in my 79 and was very easy to mount.

If you were interested in buying one of those it would be worth a trip to a junk yard to take a look at them first and pick up the mounting brackets with their little rubber isolators before hand.

 

Subscribing. Will be doing this sometime soon too.

 

I think I've about figured out what I'm going to do. I'm going to get the largest modern universal parallel flow condenser I can fit (much more efficient design than tube and fin condensers on our trucks). They're pretty cheap on eBay 50-100$ Once it's mounted I'm going to get some lines made for it to accommodate the factory drier. There all common fittings so it shoulnt be too much trouble.

If you want to make a custom line the easiest way I've found to do it is take the fittings to a hose shop. Most common fittings they'll probably have, but the oddball vehicle specific fittings they should be able to braze to one of their own fittings. If you look at my original post, that's what they did on my hoses.

 

So this all I have done in a few months... I ordered a parallel flow condensed and mounted it in place of the factor condenser.



Now I just need to mount the sanden air compressor, and drier and make up some lines. Maybe my next installment will be a little quicker!

 

Compressor



and the hoses. I just had the original high pressure hose from the compressor to the condenser rebuilt, it fit like factory. The other high pressure lines I had made up to go to a new and larger receiver/drier and to the txv and evaporator.



Factory high pressure line ^^^



Condenser to drier ^^^



I built a bracket to hold the new drier, it attaches to preexisting bolts on the radiator support.

 

I drew this system into a deep vacuum and held it for 30 minutes. It didn't lose any pressure after two hours of sitting so I deemed it worth of a charge. I charged it with 134a and alas! it was only slightly cool. Low pressure is around 25psi and high pressure is around 200psi.

Low side has around 10 to 15 degrees of super heat and the high side has less than 10 degrees of subcooling.

The AC does ok as long as the engine is hot and/or the truck is moving down the road. Once the engine reaches operating temperature a/c performance diminishes quickly. I have insulation but the heat from the exhaust and engine still makes it way into the cab, and the AC can't keep up. Bummer.

 

I am thinking you might not have enough refrigerant. 25psi seems too low but 200 psi on the high side might not be high enough either. My ac troubleshooting info says you might have a blocked or faulty expansion valve or orifice tube. Pressures are related to outside temperature too.

see this chart...

 

I will be very suprised if its still low, I've used 7 12oz cans so far.
I thought about the possibility of a defective expansion valve, but its brand new, and other expansion valves I've used yielded similar results in the past.

I do appreciate any and all input.

 

Subscribe.

I need to upgrade the factory AC on my '78.

 

I just wanted to check the low side, I wish I would hooked both side up now, but anyway I'm getting 12 degrees superheat. The factory expansion valve is rated for 8 degrees superheat. I think low side is a little high, but the ambient temp was around 85 tonight.

 

7 - 12oz cans is like 5.25 lbs. That seems like WAY to much. I was thinking (remembering) the system only needs like 2.5 lbs of R134.

 

I agree that it seems like too much, but my system will have more capacity than a stock system. The reason I kept adding is the gauges are showing a low-low pressure and a low-high pressure.

 

This might be a crazy question, but do you have the expansion valve bulb all nice and insulated (wrapped in cork tape) around the suction hose at the evaporator exit? Since you've replaced everything, I'm not sure what could be causing you the issue. With that said I don't think changing to the parallel flow condenser would add very much capacity to the system. Surely not enough to double the capacity. I hope you get it figured out though, because it's about to get hot down here.