Formal A/C question

[1978 NYB]

My 78 NYB manual A/C system was a disaster when I bought this car. The A/C system is working now and I get 39 degrees at the center vent.

The problem is the amount/flow of air flow coming out of the vents. I get some air coming out of the vent but it is minimal. I had to replace the blower motor. I normally replace the squirrel cage every time but I didn't have time to wait for a special order squirrel cage so I used the old one. I can hear the blower motor spinning at all speeds including high speed and would think all the noise would indicate that the squirrel cage is spinning. The only thing I can think of is that maybe one of the vacuum actuators isn't opening a door fully or at all and allowing the air to flow through the vents. Which actuator would that be? Is it possible that I put the squirrel cage on backwards and the air is blowing in the wrong direction?

Stan / Mr. C .....your comments/thoughts.

 

[commando1]

Damn. I'm useless on this one Bob.
All I know is that blower system has been asthmatic in all the Formals I have seen before and after new blower motors and cages. Both plastic and steel. Formals just refuse to put out air that will slick your hair back like GM. Funny thing is GM and Mopar motors are the same. Same P/N. Gotta be crappy design of the plenums and ducts.
I once considered to putting in a 6V motor to make it run twice as fast but you know what changing those motors are like. I will not do it again.

 

[patrick66]

Could be one of the vacuum connections or lines at fault. I had a faulty switch on mine, as it would put out only on Low. Replaced that in 2010, and it works fine.

I bought my NYBS in 2007. The previous owner had converted the system to R134, which does need a recharge now.

 

[1978 NYB]

I just don't know.....I sure as hell hope I don't have to take that blower motor out again if something is wrong with that squirrel cage.

Does anyone know what position each of the doors are suppose to be when at max A/C mode?

 

[commando1]

Outside air intake closed.
Interior air intake open.
Defroster door and floor door closed.
Dash vent and under dash ball cooler door open

Posted via Topify on Android

 

[Mr C]

From page 24-89 of the 1978 FSM:

Max A/C means: All of the doors are in the same position as they are in "OFF". The Max A/C mode closes the electrical circuits to the blower motor and the compressor clutch.

Inlet air door is open to the inside of the car
Mode door Open to A/C
Heat Defrost open to heat
Compressor clutch on
Blower on
Water valve off

The blower can be operated at 4 speeds Low (bottom) Medium 1 (lower centre), Medium 2 (Higher centre) and High (top). The blower comes on in all positions (at the selected speed) except "Off".

I would select defrost and see the air flow at all speeds through those vents...it's the most dramatic and will for sure tell you if your blower is spinning.

If you had mice, (they love to build nests in there) the fuzzy stuff they use (most likely the jute backing from your sound insulation) will absolutely kill the air flow. Luckily you can look right into the blower cage with the system off..(look past the rod for the inlet air door actuator and you'll see if there is obstructions.

 

[1978 NYB]

Thanks Mr. C

I will do some checking and report back.

 

[tallhair]

Outside air intake closed.
Interior air intake open.
Defroster door and floor door closed.
Dash vent and under dash ball cooler door open

..............................................

 

[commando1]

What do you call them?

 

[patrick66]

Lower vents.