What is this part and hose outlet and factory A/C questions

[cortcomp]

Hey all! First, great place and thanks everyone for all the comments and help on my build thread.

Second, i've been getting everything engine bay related out of the way, and i see three outlets from the AC evap box. Two have hoses and look like the normal setup i'd expect to see...third i don't know what it is and what connects to it? Some searching hasn't turned anything up.

Secondly, can i flush the evaporator? Except for that mystery tube, i don't think it's been open to air, but you never now. If so, what can/do i flush it with? And can/how do you test them? I hate to take that out and replace it, they're pricey.

I am putting a new compressor/drier/condenser and hoses (new sanden type compressor) so if there's anything else i should know, chime in!

And do hose clamps really work on an A/C system?!?!


Lastly, second picture, it fell out when i took the motor out, looks like some kind of mount cushion, only found one, can't seem to make sense where it goes. Truck catalogs don't show anything like it. Ideas?

[HOTFUN]

The mystery outlet has a tube that attaches there to the fan motor for cooling and air equalization of the fan motor itself and the inside of truck when recirc air is being used from cab interior only.

I am doing same thing as you on my frame up here shortly. I take the evap core totally out and flush the core without the valve with ac flush from auto parts store in quart cans. I use a pressurized gun that takes the cleaner through the core and out the other outlet. Then I just blow it back out and leave it to dry for several days before assembly. The fittings I plan to have regular ac line ends professionally welded on where the barbed clamp ends are now so that I can make up new nut o ring style ac lines with crimped on parker ac hose.
The fittings are available at auto parts stores also.
I too will upgrade to the new style compressor and a cutoff switch and R134.

Don't know what that pad was from at this time.

[cortcomp]

Thanks for the info! that makes sense, i had read somewhere awhile ago about a heater motor cooling tube, makes sense! so it being open hasn't contaminated the evap at all thankfully! I will look for some AC parts flush. Did this style system not have a cut-off switch at all?!

[VictoriaHardware]

That cushion looks like the one on the belhousing-to-frame mount. I'm guessing you have a manual trans?

[billd5string]

That looks like the bellhousing to frame bushing to me as well.

[cortcomp]

It probably is that....there should be two of them correct? I just found one, but maybe one was missing?

Thanks for the AC link, i have the service manual and it shows two hoses, that's why the three confused me, but i guess it's really not part of AC....i did read on one of these forums about that cooling hose for the fan motor, i just didn't recall the info.

I'll look for the shut-off switch, i just thought that the thermo controlled switch behind the glove box with the capillary tube did that for this system, i will go over the the docs with more detail.

Thanks again everyone for the help, and i'll print this AC stuff out to compliment my manuals!

[cortcomp]

And i see from this link already that i have an original AC fan instead of the clutch fan. I still will likely go to a large factory 7 blade clutch fan. Love these little tidbits though!

[HOTFUN]

Mine did nto have the fan clutch just the 5 blade fan mounted with a 2" spacer and 2 seperate steel pullies on the water pump. I bought a new NAPA thermo fan clutch with the correct 5/8 bushing size and new set of short studs for the water pump mount. I will use the original ac steel pullies to save on the tremendous long hanging weight that cast pulley weighed on the original HD cooling systems styles. I dry run fit the new clutch and it bolts up perfect to the studs and appears the fan will set near the same exact position in the shroud opening.

[HOTFUN]

On the evap core I will use a new bypass valve on that small cooling line but I was going to also add a high pressure switch as Vintage Air recommends out near the evap core.

[chevyrestoguy]

Originally Posted by HOTFUN

....I am doing same thing as you on my frame up here shortly. I take the evap core totally out and flush the core without the valve with ac flush from auto parts store in quart cans. I use a pressurized gun that takes the cleaner through the core and out the other outlet. Then I just blow it back out and leave it to dry for several days before assembly. The fittings I plan to have regular ac line ends professionally welded on where the barbed clamp ends are now so that I can make up new nut o ring style ac lines with crimped on parker ac hose.
The fittings are available at auto parts stores also.
I too will upgrade to the new style compressor and a cutoff switch and R134.

I am doing this exact same mod as well.
I flushed out my evaporator using an A/C cleaner in spray form that I bought from NAPA. I was surprised at how dirty the solution was when it first went through the evaporator. It cleaned up pretty quickly, and then I blew dry shop air through it for about 15 minutes.

HOTFUN: Have you had any luck getting weld-on fittings for your evaporator? I plan to use Male ends because the female ends are much larger and may cause an issue when trying to get the evap assembly installed and through the firewall. I'll use female ends on the hoses. I also need to figure out where I'm going to put the low and high side pressure fittings. I'm running an R4 compressor, and the manifold fitting I'm using needs to snake past the valve cover, so there's no room on the fitting to add the service ports. I may get the 90 degree fittings that have the service ports and put them at the hose connection that mates to the evaporator. I'm going to mock everything up with heater hose and get my routing where I like it and then buy all the barrier hose I need and have the ends crimped on.

I've got my evaporator box completely disassembled and all of the parts have been blasted and painted. I still need to buff out the plastic housing because it has silver overspray on it from the previous owner. All of the electric components on the top of the unit are available in the aftermarket except for the blower motor switch that operates off of the flapper door inside the unit. Haven't found that yet, but you can find the thermostat rebuild kits, the correct resistor, and the correct 4-post blower motor relay on Old Air's website.

If you're planning on rebuilding your set-up, you'll find that nobody makes a gasket kit for anything on the A/C system, and the stuff that's available for the heater box is a joke. The gaskets are about 1/3rd the thickness of the original gaskets. Typical aftermarket quality......

I'm anxious to hear any info you guys have discovered while converting your original systems to R134. I'm going to try to make my system work as good as it possibly can. I'm sealing up all the gaps, making the gaskets seal better, and insulating wherever possible.

Last question: I think that the A/C system can work even better if you have the capability of shutting off the hot water supply to the heater core. I'm going to add a shut-off valve because the fresh air has to go through the heater box, which has a heater core with 180 degree water flowing through it. What do you guys think about this? Do you think it'll make a difference in the A/C temperature?

[cortcomp]

Lots of aftermarket AC controls shut off the hot water supply through the heater core, and also my packard had a shut off for summer. It's good anyways, just radiant heat once warmed up is enough to warm the cab, that's all we had on the way home from CA in the cold texas morning, and it made the whole dash hot, no blower fan working. Shut off valve is good idea.

I can see the high pressure switch, just figured the thermo switch in the evap/glove box would do the same. Easy and cheap enough to add and wire (two prong can be right by firewall, and clutch wire goes right by there anyways, cut and put on spade connectors.

Brackets are kind of pricey. They're stamped steel. Wtf.

I will run 7 blade 19" clutch fan if i can find one (they are rounded edges and offset blades, so quieter than solid spacer fan from dealer install AC kit) and hayden clutch. Shouldn't be as loud at mid-upper RPMS.

I've been using old air products, will be giving them a call before i get to that point. Will probably be lazy and use hose clamps at firewall like factory.

[HOTFUN]

The fittings are very common in Everco catalogue and local parts houses have their books full of all styles and sizes of fittings. I have not done this yet on this 66 pickup but have done several others on custom built projects such as my VW Rabbit pickup with a TDI install. You bring up a good point on the firewall install. I hoped the hole would be large enough to slide box up and in with new male fittings in place. If not I will have to enlarge the holes and seal them back with 3M strip caulk. I planned the same exact logic in female ends and cutting the parker hose to physical laid out length then taken off to have crimped. I was using the new replacement sanden style compressor that fit the original brackets. I was hoping to use the original muffler compressor fitting and weld new fittings on and install the R134 ports in the original install. Second would be to add the port via a new hose fitting with the port capability at he evap core on the engine side of the firewall. I may have said Vintage Air but it was Old Air that has a good selection of parts and the pressure cutout switches for the lines. I'm no expert jsut done a number of these rebuilds over the years and I want them to work better than my new 2013 truck so I try and finess any place I can gain effeciency and still try to hide the upgrade for a factory stock appearance. Would be neat to rework a shutoff valve in the heater core case but then many vehicles like the Dodge Ram trucks in the 94-2001 models use a continuous flow heater core and remove the air flow across the core. I probably will try it first before I go to a lot of work to change it.

[cortcomp]

Even a simple shut-off valve by hand in the supply that you turn off during the summer would be fine:



But a lot of aftermarket people use this style that is run by a cable, you could add a second cable to your A/C controls if you were creative, so that when you slid the temp control from hot to cool that it also shut the valve, or maybe when you pull the A/C knob on it also closes the heater core flow:

[jayoldschool]

80s RWD full size Cadillacs use a heater cut off valve if you are looking for a "factory" type solution.

[64fleetside]

I used male fitting on my evap, they will pass thru the firewall hole but it is very tight.

[chevyrestoguy]

Originally Posted by 64fleetside

I used male fitting on my evap, they will pass thru the firewall hole but it is very tight.

When I did the body work and paint on my firewall, I temp-installed the evaporator assembly and then tightened up the feed-thru holes in the firewall by welding in a filler panel that put the holes in the exact spots that they come through. My plan is to use bulkhead grommets to make the evap tubes as air-tight as possible. Wind noise and whistling drives me nuts. I can see a bunch of areas on the heater and A/C installation that could be potential "whistlers", and I'm trying to address each one and still make it all look factory.

"But a lot of aftermarket people use this style that is run by a cable, you could add a second cable to your A/C controls if you were creative, so that when you slid the temp control from hot to cool that it also shut the valve, or maybe when you pull the A/C knob on it also closes the heater core flow":

I have thought this exact same thing. I don't have my heater controller in front of me, but two of the levers are identical, and they have two cable attach points at the opposite ends of the lever. It would really be slick to have it where as the lever goes up to the Cool position, the opposite end of the lever closes the heater valve. The cables had better actuate smoothly though, because you don't want to have too much force on the levers because they are made of potmetal and they will break over time.

[64fleetside]

Originally Posted by chevyrestoguy

When I did the body work and paint on my firewall, I temp-installed the evaporator assembly and then tightened up the feed-thru holes in the firewall by welding in a filler panel that put the holes in the exact spots that they come through. My plan is to use bulkhead grommets to make the evap tubes as air-tight as possible.

I think originally there was a rubber seal on those hoses-I used some rubber to re-create one. Mine works great but it is somewhat noisy compared to newer vehicles-a lot of air comes out that single vent.