Re: AC compressor fittings

[Tom Jennings <tomj@xxxxxxx>]

On Sat, 17 Sep 2005, Marty Bricker wrote:

Umm first, and you probably don't want to hear this, take the car
to a competent A/C shop. For $700 you could have a complete,
brand-new aftermarket A/C system, all new parts. hoses and
compressor. I hoep they've changed all the hoses, the dryer, and
you got a new compressor for that much money!

My experience here in Los Angeles -- where everyne has A/C in
their car because it does get hot -- I had a hell of a time
finding a competent place. I basically never did. The one place I
trust their machine was out being serviced; Pep Boys wanted far
too much money and they can only "look things up onna compooter",
and a small, local shop proved to be utterly incompetent.

Yellow pages, look for A/C specialists, wait in line, get
competent service. Look for hotrod places, they usually don't hate
old cars.

I am NOT an A/C expert, but I did do a couple of go-rounds with
the fittings.

I don't know if by 83 they'd moved to all O-ring fittings. The
older alternative is plain flare fittings. Which do you have?

First, to set this aside, the hose O-ring fittings basically do
not leak if the O-rings are good (pennies each, new) and the metal
is not nicked, corroded or out of round (eg. stepped on). If
they're leaking, someone overtightened them. O-rings don't seal by
compression; they seal based upon the simple fact that at the
microscopically tiny area where a circular O-ring meets a flat
surface, even 1000 PSI generates no pressure. (it's pounds SQUARE
INCH; if you have .000001 square inches, the force at the O-ring
surface is essentially zero). They only need to be tightened
enough to not come loose.

If they can't make an O-ring fitting work perfectly on the second
try, they are incompetent.

I assume you have a Sanden compressor? The round type, not the
lawnmower-engine type (York).

Service fittings: my knowledge is very thin here, don't take my
word for it!

All A/C systems have a pair of fittings to which are connected
gauge sets, fill tanks, vacuum pumps, etc. This much is certain.
Newer systems are a quick-connect, self-sealing type. Older
systems have a two-way valve and are serviced differently (caveat
emptor; look in you technical service manual, I'm too lazy to go
get mine out of the lab :-) While the stem of the valve may leak
(it's got a packign like a faucet) when in the NORMAL position,
there's a face seal and I doubt that will leak unless there was
corrosion or some monkey overtightened it and ruined the face.

The service fittings may be on the compressor or the hose ends (my
Rambler's H134a Sanden system has them on the hose ends).

Are the fittings leaking out the hole? Or where they are attached
to the compressor or hose? If there's any pressure at all, you
cancheck for external leaks with soapy water.

A/C is annoying, but it's not rocket science. Mechanically, it's
pretty trivial, none of the parts are particularly exotic, though
I've never had a pump apart (yet) and basically no one repairs
them, only R&R.



> OK, I haven't seen any thread on this but Firestone is
> saying the a/c in my daughters 83 Spirit won't hold a
> charge because the service fittings are leaking.  I
> tried to order new ones from Chrysler but the fitting
> for the hose side is incompatible.  I purchased a set
> off of Ebay that, supposedly, came off of a working
> system but they said they also leak.  Before taking
> the set I purchased in off of Ebay I cleaned them up
> real well.  I didn't see any evidence of a rubber
> fitting that would seat.  Has anyone had this problem
> before and how have they fixed it?  Are new fittings
> available anywhere?
> Marty
> PS  Firestone has been working this problem for over
> two months and charged me almost $700. to replace the
> hose and fix a leaking evap unit (so they say).
> PPS  This system worked great last summer
> PPPS  I did tell them to ensure the valve was fully
> open or closed and they said it still leaked
>
>
>
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