405 A/C questions

Clifford M Poulin (cmpoulin@cisunix.unh.edu)
Mon, 14 Jun 1999 12:50:22 -0400 (EDT)

Over the years the A/C system on my 1989 405 Mi16 has faded in its cooling
until last year it was completely empty of freon. I noticed a dark,
greasy looking area around where the aluminum A/C hoses go through the
firewall, so yesterday I removed this connection and saw that the original
O-RING on the large hose had been pinched and warped during assembly in
1989. I'm 99% certain this must have caused the very slow leak. I
replaced both O-Rings and put everything back together securely.

1. Has anyone else had a problem with leaks at the firewall? Did
replacing the o-rings solve the problem?

2. How is a system pressure tested for leaks these days? What do they
use to pressurize it? Any idea where the pressure is connected to in the
system? What pressure does this type of system operate at?

3. What is the freon capacity of the 405's system? What is the going
rate of freon these days?

4. Since the system has been empty of freon for a year, is it necessary
to replace any parts in the system. What would happen if I didn't and
just had it recharged?

5. What is the content of the freon? Is there some sort of oil mixed
with it?

6. Does anyone know of a good source of general information on Auto A/C
systems? (web or otherwise?)

Thanks for any information. I am mechanically inclined, but I know almost
nothing about Automotive A/C systems.

Cliff