big day of a/c work starting tomorrow

[treed2 at wsu.edu (T. Reed)]

Hi all,

First I wanted to share a link I found today while looking for a place to 
rent an A/C vacuum pump:

http://www.honda-tech.com/zerothread/1665946

If you can get past the 'honda' thing, there's some decent information 
(and pictures) here. Some of it is a little bit off, but nothing too 
serious.

It turns out that as explained in the link, Autozone will loan you the 
vacuum pump for a $200 deposit which is returned in full when you bring 
the pump back. It's hard to get a better deal than that, although in the 
thread many people had trouble finding an Autozone that had a pump to loan 
them. The author is in Phoenix and I'm in Tucson.. so maybe it's just an 
Arizona thing. I don't know.

I borrowed the pump tonight and supposedly they want it back in 3 days so 
I'm scrambling to get things together so I can work on the A/C for the 
next few days after work. I had been planning to do this work over the 
weekend and I still might have to, but I'm a little concerned that the 
manager wasn't joking when she told me "you bring it back late, you bought 
it", or something along those lines.

I bought a manifold gauge/hose set from them for $49. It looks like it's 
going to work but if not I can return it and spring for the $79 set.

I ordered a receiver/dryer ($17), expansion valve ($27), and a set of 
o-rings ($20) from Autohaus AZ on Sunday. They are to arrive tomorrow via 
UPS. I already have the r134a high and low side fittings from a previous 
attempted conversion.

My whole formerly-installed A/C system is sitting in a pile in my garage 
so I have to re-install everything before I can pull a vacuum and charge 
it up. If I'm lucky I'll be able to put the system together in one evening 
and pull the vacuum/charge the next. In fact, I'd better be lucky since 
this is my only car and I have to drive to work in the morning!

First order of business is the expansion valve. I took the old one off.. 
for some reason it was buried under a mound of white goo not unlike 
highly-sticky poster putty.

Then I'll put the condenser back in in front of the radiator, and the 
associated hard line with the pressure switches in it. Then the 
alternator, ps pump and water pump come out so I can put a new bracket in 
for the a/c, and put all of those back on it (and the compressor this time 
as well).

After that I'll feed the lines back through the firewall and hook them up 
to the compressor and condenser. I'll put the dryer in place with the caps 
still on and leave the lines to it unconnected for the moment.

The flap of plastic I cut in the heater box gets folded down, then I'll 
slide the evaporator and expansion valve assembly, along with the 
thermostat, in to the heater box and hook up the a/c lines to it. The 
thermostat will get mounted back up inside the dash with the hvac 
controls. I'll be putting new o-rings everywhere that a connection is made 
between lines or components in the course of all of this.

The electrical for the compressor clutch and pressure switches has to be 
re-connected, then I can open up the new dryer and connect it to the 
lines.

At that point, I will hook up the manifold and start drawing a vacuum 
through it with the pump. After I have a good enough vacuum I'll give it 
some time to leak down (hopefully it won't) then if everything is good 
I'll hook up a can of refrigerant, purge the air from the lines then add 
it as a gas (with the can upright). Same for the oil (but as a liquid, 
duh), then repeating the process for the second can. I'll be keeping an 
eye on the gauges to see if the system pressures fall within the bentley 
chart.

After the charge is finished, it will be time for a drive.. and hopefully, 
I'll have A/C that works well and continues to works well for the weeks, 
months, years to come so that I don't have to work on it again. At least 
that's what I'm hoping for after trying to do everything "right".

Here are the questions I haven't answered for myself yet:
- should I oil the o-rings before installing? If so I'll need to get some
   oil in a plastic bottle rather than in the ready-to-charge can

- should I charge with the oil first or the r134a?

- how much oil should I charge with? 2 oz? 4 oz? It's probably in the
   bentley, I just need to look it up.

- should I charge with the engine off (relying on the pressure
   difference between the cans and the vacuum) or with the engine and a/c
   system running (my gut tells me to have the system turned on.. that the
   compressor will be off until the low pressure switch decides that there
   is enough pressure in the system to not damage it)

Anyway, I'll post when it's all over to let you guys know how it went.

-Toby