1956 400 - AC Evaporator

General topics, not covered elsewhere, of all things Packard.
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PMCCTX
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1956 400 - AC Evaporator

Post by PMCCTX » Tue Mar 12, 2019 4:03 pm

Replaced all the hoses on this car (they were 63 years old and brittle) - went to recharge the system and found the leak to be on the back side (yes under the dash) of the firewall.
SO...it looks like I'm facing a major project in order to get the AC working again on this car. Does anyone have any insight on the nightmare it's going to be in order to remove the AC evaporator?

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Leeedy
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Re: 1956 400 - AC Evaporator

Post by Leeedy » Thu Mar 14, 2019 9:12 am

There is no real shortcut here. If the leak truly is inside the evaporator housing there is only one option:

• un-bolt the steering column, disconnect all of the electricals with it (horn, turn signals, pushbuttons) and remove the entire column.
• un-screw and remove the bakelite vent doors on top of the instrument panel.
• un-screw the instrument panel... loosen the pivot bolts and tilt it down...
• detach any and all electrical components and leave them hanging
• detach the evaporator housing connections on the engine compartment side (best to use A/C wrenches). Use care not to strip threads.
• pull the evaporator housing... take it to a competent repair shop. Usual break is at base of connection between the core and hose fitting.

reverse the removal to reinstall.

Last edited by Leeedy on Thu Apr 04, 2019 12:21 am, edited 1 time in total.

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Leeedy
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Re: 1956 400 - AC Evaporator

Post by Leeedy » Thu Mar 14, 2019 9:32 am

I guess I should mention that the most common way an evaporator leak occurs on 1955-65 factory air is if a hose is removed/detached on the engine side without using TWO A/C wrenches. There is not enough strength on the hose fittings where they join the core. So IF the core side of the fitting is not strongly prevented from twisting (by using 2 A/C fitting wrenches) when detaching a hose, the fitting will simply snap off or rupture from the core where it is fitted. And the rest is academic... adios muchachos on the closed seal and you've got a breach mess on your hands. I've seen this happen several times when either hoses are being changed or a system is being pulled from a car.

PMCCTX
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Re: 1956 400 - AC Evaporator

Post by PMCCTX » Thu Mar 14, 2019 9:53 am

That's exactly what I figured but was hopeful of a miracle shortcut. Silver lining - gives me an opportunity to repad the dash, fix the speedo, and change out the headlight switch.....Think I'll be running sans AC this summer and tee this up as a long winter project. Thanks for the input!

Howard56
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Re: 1956 400 - AC Evaporator

Post by Howard56 » Thu Mar 14, 2019 7:09 pm

You can go to www.packardinfo.com and when the literature page opens select Service, Shop and Training Manuals. Item 43 is the 55-56 AC Field Install Guide supplied to dealers so they could install the factory AC system in customers cars. It has several photos of the unit and procedure so will give you a good idea of how things mount. For removing the evaporator only you do not need to remove the dash but the glove box and radio will need to be removed. It is an extremely tight fit under the dash and some of the screws on the evaporator case will be a bit hard to get to. There are only a couple of screws on top but most of the case front slides into a groove along the top edge of the box and could be stuck if the insulating rubber has deteriorated or was well glued over the front of the slot or groove. You are correct in that it will be a project.
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Leeedy
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Re: 1956 400 - AC Evaporator

Post by Leeedy » Fri Mar 15, 2019 11:16 am

Howard has his method... and–respectfully– I've got mine. And I've pulled and installed a bunch of these 1955-56 A/C units, I assure you. A bunch of them over the years. I've also sent others to pull systems at junkyards for me (that's how I know about the break-off issue when 2 wrenches are not used).

Regardless of what is possible and what manuals say, you'll be far better off just pulling the instrument panel and getting it over with and don't even fiddle with removing other stuff that is likely to get damaged. It is a very simple operation and if you first tilt it back like I mentioned, you'll save yourself a lot of time, a lot of feeling around in the dark, cuts and scraped knuckles and frustration. Plus you can see everything, including whatever else may have degraded under there in all these years.

And this doesn't need to be a huge or a seasonal or long project. You could do it in a day. And re-padding the dash? IF the vinyl is not badly damaged (or turned into a Southern California potato chip) , my usual time was 24 hours... and you can do all this while doing your A/C evaporator. Did dozens of them back in the 1970s (using motorcycle seat foam and a heat gun).

Howard56
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Re: 1956 400 - AC Evaporator

Post by Howard56 » Fri Mar 15, 2019 1:20 pm

Leeedy is right if you are going to work on the dash padding and check for any other behind dash problems because that kind of stuff is almost impossible with the dash in. You can barely get a hand behind the dash in an AC car let alone get your head up to see anything if you want to do much work.

I only said the evaporator could be removed with the dash still in because it is somewhat more of a project to remove the dash and some are just not equipped physically or sometimes even mentally in wanting to tackle the project.

As to what can be done with the AC unit with the dash in, if you are a contortionist and glutton for punishment, plenty. I didn't want to remove the dash again so removed my entire unit, copied it and made another complete and almost exact duplicate unit and installed that one so I could have a unit that used modern parts and R134A. I did remove the front seat and the 56 steering column for better access. If it had been a 55 the non removable steering column would have been a factor that might have decided toward the dash removal. I am proud to say that once the new unit was in (except for a glaringly obvious Sanden compressor) it would take a Packard person very familiar with factory AC to know the difference.

While there are those that will wonder why, the reason for a duplicate modern unit was that both my original modulator valve and compressor were not functional so the AC was inoperative. Since there does not appear to be an abundance of new/used items or a place to have the valve repaired or obtain new compressor valves and gaskets that made the decision. If someone knows of a place for either I would sure appreciate the info but in this case, rather than try to mickey mouse and possibly do more damage to an original unit I decided to remove and preserve it until the time where possibly the parts needed can be found or repro'd. The only thing stock I kept in operation was the rheostat switch and the blower assy. Instead of the modulator valve and hot gas bypass providing the fixed temp, ice prevention and a variable temp control is now via cycling clutch and a cable controlled thermostat. Since the two functions are complementary, by adding another stud and Bowden cable to the temp control lever the AC thermostat could be operated by the same lever that works the heater thermostat. With the functionality at opposite ends of the lever travel, operation wise a bit more leeway in temp adjustment and no one is the wiser.

This is my copy where I made everything including vents and ducts.
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Leeedy
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Re: 1956 400 - AC Evaporator

Post by Leeedy » Fri Mar 15, 2019 6:44 pm

I have not done a Packard factory air system in a long time, But the folks who had all of the parts were a nationwide string of shops that fell under the name of "ARA"... In southern California there were several ARA facilities... Fountain Valley, downtown Los Angeles, Ontario, California. All had good-sized warehouses and stocks of Packard parts into the 1980s. My understanding is that ARA dissolved in more recent years but a lot of the old shops and parts stocks were still around at the time. Just ten years ago I had them re-do one of my Cadillacs. The shop name had changed but they still had a lot of vintage parts... like a NOS compressor and hoses for my Cadillac.

If it were me and I had the time and I was doing Packard V8 factory air units, I'd go out and start tracking down just how many of these old guys are still around. There was a place in SoCal, for instance, that still had expansion valves, thermisters and other parts. Frost & French (now long gone) still had NOS dash top vents in the 1970s. No idea what happened to all this good stuff. But it was once sitting around. Of course, has anyone asked our friends at Kanter what A/C parts they have left?

And if all this fails, yes, making new guts for an evaporator unit out of modern parts ought to be an option–and a good one. It would appear that Howard has that all worked out. And since R-134 has replaced R-12 anyway, the move to a hybrid evaporator core is a viable one.

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