Air Conditioning in my 1964 Cadillac

[Robert Sweeney]

I bought this beauty a year ago and at that time the AC system was flat.  I replaced a line that had a huge hole in it, pulled a vacuum, charged it with R12 and it started making cold air !!!! Oh happy days !!!

AC runs great until I take the transmission out of Park (and put it into Drive or Reverse).  At that point it just fan shuts down.  If I put it back in Park the fan starts blowing cold air again. 

What the heck ?   My only thought is that it might have something to do with the neutral safety switch (it hisses when I put car in Drive). 

Any suggestions ??

[Kurt]

[2o93f8rdftyzj]

Did you reply in invisible ink?

[Kurt]

No. Weird. It was a really good reply too that I don't have time to re-type. I'll sum it up by saying find the source of the vacuum leak & it should fix the problem: hoses, NSS, check valve, auto-release for parking brake, etc. All under the dash near the steering column.

[24ro8f5mbs2jc]

I always write my posts in invincible ink...   ;-)

[2o93f8rdftyzj]

Superman branded invisible ink, making it invincible ink.... geez Tony, don't you know nuffin.

It might be time now to put Roberts thread back on track.

 

[0hsy7we8jmzty]

There is a vacuum circuit diagram on either page 13-20 or 13-22 of the 1964 shop manual - if memory serves - I don't have it with me at the moment.  That diagram shows that the vacuum to the NSS and the vacuum to the control head of the Automatic Climate Control inside the car, are interconnected. There may also be a check valve in the line.

[Robert Sweeney]

Update -  See attached picture.  I found this line disconnected under the dash.  Thanks guys.  Air not blowing real cold so I'm going to check the charge.  I bought the bible on fixing 1964 cadi ac systems last year.  I have to spend some additional time with my nose in that book.

Thanks again.

 

[3ft7bqmb7dryo]

That's good, troubleshoot first. Then buy parts.

[Kurt]

No problem Tony. I've been called much worse : )

[Robert Sweeney]

Hi Guys,

Thanks for all your suggestions.  I have been troubleshooting the AC pneumatic system and all things point to the "rotary valve" on the passenger side interior.  I bought the $20 manual and it gives direction on how to recondition the rotary valve.  It doesn't sound too difficult.  Has anyone done this before and do you have any advice ?

[Robert Sweeney]

Thanks .  Just got done refinishing the valve.  No big deal.  Not very intimidating (once you've done it).  Thank for the advice.