AC System Clogged

[Tim Cole]

In the process of restoring my 79 Bird, I replaced the AC system with new parts and retrofitted to R 134a. It blew ice cold.

But it didn't blow as hard as it should have. I tried to find the problem. My AC ducts were clear. The fan switch worked right. I blew out the cowl ducts. Still no solution.

So, I bit the bullet and dropped the blower motor (under the dash). Eureka. The evaporator core was chock full of insulation (from the fire blanket) and leaves. Once removed, the system blew hard.

Now, it's ready for a Florida summer or an interested buyer!

 

[bigbrownbird]

hey!

maybe that's why my heater or air doesn't blow quite like it should! Thanks tim, now I won't sweat on those brown leather seats in august or freeze me tootsies off in Early november (before the snow, of course)

Lee

 

[Tim Cole]

Lee:

Per your comments, I noticed that both the warm air flow (heater) and the AC air flow were greatly restricted.

But now--with the blower motor area cleaned out--the air flow is very strong. In fact, it blew so cold and hard today (on a hot Florida day), that I had to turn the fan down to 2nd speed (out of four).

Hope you have the same success in cleaning it out.

Tim

 

[bigbrownbird]

Tim,
glad to hear you're chillin' on a hot Florida day. I was wondering about your 134 conversion, I am planning on converting as well when I put the 474 in my car, with the exception of using a newer AC pump off a 96 f-250 (smaller, lighter, and can use the serpintine belt I want to use.) any info on where you got hoses, any other parts, and any tips would be greatly appriciated.
thanks,

Lee

 

[Tim Cole]

Lee:

Regarding conversion to R 134a: When I retrofitted my '79, I put a new compressor, new expansion valve, and dryer on. Everything else stayed the same (accumulator, evaporator core, AC lines, etc.). All odf these items can be purchased a local auto parts store.

In principle, all you need to retrofit the sytem is to change the fittings, evacuate the system (need a pump to do this), and charge the system with new refrigerant. But putting on a new dryer is usually recommended when you do anything to the AC system.

And, what is more, if you really want to do it right, it makes sense to change the expansion valve and compressor as well. If your AC lines are still healthy, keep them on. If they need to be changed, NAPA has them, as do other auto part stores.

Best wishes,
Tim

Most auto shops can do this in a short time.

Tim
When you buy R 134a at the store, it will often come with the new fittings.

 

[Charles]

Makes you wonder where all that crap comes from. Presumably those 2 pieces of plastic screening up at the cowl where you access the wipers. After cleaning out all my debris (thanx for the cool tip, Tim) I contact-cemented screen door mesh to the backside. Let's see if it works.

 

[Tim Cole]

Charles: I Haven't tried glueing screen door mesh to the cowl vents, but, if it keeps out junk, so be it.

I found many pieces of the fire blanket in my evaporator core and blower motor (the fire blanket is the insulation pad under the hood--in case of fire in the engine bay, it's supposed to drop down and smother the fire).

In any case, I ripped the old one out and replaced it with an almost new one. Periodically, I vaccum out the passenger side of the cowl vent. The driver side is way too small to do anything with the vacuum. It also clogs up easily due to its small size.

I guess Ford didn't have "a better idea" on this one.

But in hindsight, the AC/heat blower motor in these Thunderbirds is one of the best ever produced. I have never heard anyone complain that their blower motor burned up with normal use. They can really put out the AIR!
Tim