Restoring and swapping a factory Air Conditioning system

[cjmdjm]

Hi guys,

My question relates to a C65, not a pickup, but I imagine the A/C systems are pretty similar from C10 to C70, correct me if I'm wrong. If anyone knows of a good chevy "big truck" forum, let me know.

I've got a couple C65s (both 1975s), one I use to haul grain, and one I bought for parts. The parts truck has factory A/C (minus the compressor). I saw online that used or rebuilt compressors aren't too expensive for most vehicles. I would like to swap the A/C system into the grain truck. The dash is much better in the parts truck anyway, so I'll swap them to get the A/C vents.

The main thing I want to know is exactly what model of compressor I need. Sites like amazon and ebay have tools to tell you if a compressor will work in your vehicle. But they don't work for anything larger than a C30. Would a C65 use the same compressor as a C30 of the same year? Both my C65s have 366 engines. Also, does anyone know where the compressor mounts on a 366 engine? If someone has a picture, that would be awesome.

Has anyone done something like this before? Are there any tricky problems with switching the condenser and evaporator/fan? The compressor was removed years ago, and one of the lines wasn't plugged. Do you think I can get the condenser/evaporator cleaned out with a bunch of A/C flush fluid? I assume I'll need a new expansion valve and filter too, right?

Thanks guys! And my apologies if this doesn't belong in a Pickup forum. Thanks!

[Desert1957]

I'm not sure about the swap, from larger C series trucks.
I might be able to measure a truck from work, I think we still have one with that cab style.

On your second question , the Compressor swap , I highly recomend the "Sanden" compressor, its much quieter and draws a lot less from the engine. Brackets to mount to the engine are available ,but it the hoses will have to be a custom fab job. Just mount it , buy the fittings you need with the hoses , cut to fit. Then have an A/C shop do the crimping or buy your own tool.

I don't know how much A/C experience you have , but it will be worth the swap.

Desert

[cjmdjm]

I'm not sure about the swap, from larger C series trucks.
I might be able to measure a truck from work, I think we still have one with that cab style.

I'd appreciate that, if you have the time. The 2 trucks are the same model and year, both 1975 C65s with 366 engines, so I was hoping the bolts and screws holding the evaporator/condenser would line up with holes in the other truck.

The Sanden compressor sounds great. Do you know exactly what model of Sanden compressor I would need? Thats been my biggest problem. Googling "which compressor for a 1975 chevy c65" or something similar turns up nothing useful.

I have some experience with A/C. I did a compressor kit on my modern chevy pickup a year ago. I guess the other thing I'm worried about is how many years that condenser/evaporator have been sitting there. One of the lines wasn't plugged. Can I get it cleaned out well enough with A/C flush fluid?

Also, will the factory lines and hoses in the parts truck connect to the Sanden compressor?

Thanks for your help!

[Goldfinger]

try to stay away from the Harrison style compressor, Mine feels and sound like im towing a good size load when i switch it on.

[Desert1957]

Here is a good read from the "Vintage Air" web site, Explains components and installation tips.

There are Vendors on this site that sell a kit for our trucks.

http://www.vintageair.com/Universalapps2.asp
Sanden 508 Model (Sorry for the Large Pic)


Desert

[cjmdjm]

Thanks Desert! So the Sanden model 508 will work with my '75 chevy C65 with 366 engine, if I get a mounting bracket? Will it connect to the factory compressor lines that go to the (factory) condenser and evaporator? Or should I get a hose kit? And are the electrical connections on the Sanden compressor clutch compatible with the factory A/C control panel in the cab?

I assume I should also replace the original drier and expansion valve and filter with new ones, since the old ones are surely full of crap, correct?

There are Vendors on this site that sell a kit for our trucks.

I tried looking through Vintage Air's site for a mounting bracket for the Sanden 508 on the 366 engine, but I couldn't find one. Vintage Air's site also doesn't seem to give prices for anything. I can probably fabricate one if I have to, but if anyone knows where to buy one, I'd appreciate it.

Thanks guys!

[hatzie]

Originally Posted by cjmdjm

And are the electrical connections on the Sanden compressor clutch compatible with the factory A/C control panel in the cab?

I assume I should also replace the original drier and expansion valve and filter with new ones, since the old ones are surely full of crap, correct?

I tried looking through Vintage Air's site for a mounting bracket for the Sanden 508 on the 366 engine, but I couldn't find one. Vintage Air's site also doesn't seem to give prices for anything. I can probably fabricate one if I have to, but if anyone knows where to buy one, I'd appreciate it.

Thanks guys!

The cab panel is just feeding 12 volts to a big electromagnet in the clutch. You will need to get the right plug for the compressor end of the wire.

When you open an AC system you should always replace the drier. Never open or install the new drier till you are almost ready to vacuum the system down. Use the old drier to check the fit of your hoses and other components.

I always replace the oil to match my refrigerant, even in loaded new compressors, AC oils absorb water.

The TXV should be evaluated but if it's not packed full of crud or corrosion and it cycles properly you don't have to replace it.

If you have the tall deck brackets for the original Harrison A6 compressor you can convert them to Sanden mounts. Google "A6 to Sanden" and ignore the Audi links. There are several drop-in Sanden 508 kits that come with bracket adapters and end covers allowing you to keep the Harrison A6 fittings.

You can just replace the flexible portions of the hoses with modified lengths of barrier hose. If you do keep the OEM hose fittings replace or eliminate the muffler because you will never clear all of the R12 oil from the baffles.

The Evaporator can be flushed and re-used. If you intend to use R134 you should consider a high efficiency parallel flow condenser.

[1985-GMC]

I was going to mention the Parallel flow condenser too but hatzie beat me to it, I highly recommend one. This is the one I was going to use but money ran a little short to permit it and new hoses: http://www.ebay.com/itm/150743405871...84.m1438.l2648
I ran "R152a" refrigerant in mine btw.

You will either need to hack the firewall to fit the A/C box or cut out and weld in the piece from the A/C cab, let me know if you want pictures of that.

[rogerapage]

[QUOTE=hatzie;5451391]The cab panel is just feeding 12 volts to a big electromagnet in the clutch. You will need to get the right plug for the compressor end of the wire.

I believe that a relay should be installed, for safety and for the life of the switch. Just my opinion.

[hatzie]

[quote=rogerapage;5451516]

Originally Posted by hatzie

The cab panel is just feeding 12 volts to a big electromagnet in the clutch. You will need to get the right plug for the compressor end of the wire.

I believe that a relay should be installed, for safety and for the life of the switch. Just my opinion.

Not a bad idea. If you add a relay put it on the firewall wired between the compressor clutch and the pressure cutout switches.

I forgot to mention getting a properly sized or adjustable low pressure cutout switch and adding a High Pressure Cutout switch.

[El Campo]

Subscribed.

[cjmdjm]

Wow thanks for all the advice guys! So it sounds like I need a new drier, but the old expansion valve may be usable. Will any drier work? Or do I need a specific model that will mount where the old drier mounted and have the right fittings?

Hatzie mentioned a Sanden 508 kit that comes with brackets and fittings to match the factory Harrison fittings. Anyone know where to get that? I googled it and couldnt find it. I don't have the factory mounting brackets.

Somebody mentioned low and high pressure cutoff switches. This is the first I've heard of these. Will they easily wire up with the Sanden 508 compressor, and the factory control panel in the dash?

I'll have to do some thinking on what refrigerant type to use. I was thinking r134, just because thats what my modern vehicles use, but I really don't know the pro's and con's. Anybody have any opinions on this?

I'll have to remove the evaporator from the parts truck and see what work I'll have to do to the firewall in the other truck. I've got a more urgent project I'm working on now, but hopefully I'll get to that in a couple days. Should I make a new thread at that point? Is resurrecting and old thread frowned upon?

Thanks guys!

[El Campo]

From what I understand R12 is a superior product and cools better. That being said my 2000 Ford with 285000 miles and untouched AC blows super cold still. R12 is expensive though. It has been debunked that it hurts the environment also btw. If you use the right components R134a will blow very cold though.

[hatzie]

Originally Posted by cjmdjm

Wow thanks for all the advice guys!
Hatzie mentioned a Sanden 508 kit that comes with brackets and fittings to match the factory Harrison fittings. Anyone know where to get that? I googled it and couldnt find it. I don't have the factory mounting brackets.

Google "A6 to Sanden" ---->https://www.google.com/search?q=A6+to+Sanden&ie=UTF-8
Try the 4th link on the page for nostalgic air. There are more...
No conversion fittings. Their Sanden compressor has a head cast and machined to mate with the Harrison A6 hoses.

Originally Posted by cjmdjm

Somebody mentioned low and high pressure cutoff switches. This is the first I've heard of these. Will they easily wire up with the Sanden 508 compressor, and the factory control panel in the dash?

The system already has a Low Pressure Cutoff switch set for R12 pressures.
You'll have to add a High Pressure Cutoff port in the high pressure line. It's wired in series between the low pressure switch and the compressor clutch.

Originally Posted by cjmdjm

I'll have to do some thinking on what refrigerant type to use. I was thinking r134, just because thats what my modern vehicles use, but I really don't know the pro's and con's. Anybody have any opinions on this?

R134 takes more planning and care to do it right.

Originally Posted by cjmdjm

I'll have to remove the evaporator from the parts truck and see what work I'll have to do to the firewall in the other truck. I've got a more urgent project I'm working on now, but hopefully I'll get to that in a couple days. Should I make a new thread at that point? Is resurrecting and old thread frowned upon?

You'll need to cut out a section of the firewall opening that's large enough to give you a patch panel to install in the non AC cab. Take the fan box off the firewall on the non AC cab and the AC box off the AC cab. Look at both to see how much you need to cut out.

I'm curious... How rough is the donor cab?? If it's generally in good shape you could just swap it to the non-AC truck. It'd take about the same amount of time as cutting up both cabs and playing the welding and wiring game.

No need for a new thread. It'll be easier to follow if it's all in one place.

[rogerapage]

R134 low pressures are lower than R12 and the high side is higher when under pressure (running) r134 is prone to leak when used in a r12 system. R134 systems have better seals and the lines are crimped different. I recommend that you do not use any refrigerant with stop leak or that has oil in it, add the oil seperate from the refrigerant. Just my opinion.