[xj-s] A/C convert to R134a (real long)

[Harry <traff@ICON.HMSD.UFL.EDU>]

I finally got cold air for the first time. After a few months of
procrastination, it's finally (sort of) done.
I originally bought a rebuilt A-6 compressor, hoses, reciever/drier, and
a new expansion valve just because it was cheap. Got it all from one of
our fine mail order vendors on the list.

The XJS compressor has a Jag sticker that states it holds 2.5 + -.25
lbs. freon, and that it takes 10 oz. oil. Well that's pretty straight
forward. I drained the new oil (6oz.) from the new compressor because I
didn't know how much was in it. I had a lot of trouble removing the hose
on the evaporator that connects to the fuel cooler, and you don't want
to break that pipe on the evaporator. To get tools in that spot, I had
to remove all the pipes and hoses at the back of the engine. While work
was in limbo, I left the old rec/drier in place. Don't want to install
that new one until its time.
From the local auto parts stores, I got all the new 'O' rings, flushing
liquid, polyol ester oil, 4 cans of 134a freon, an "Acme Threaded Can
Tap Valve" and the 134a charging port adaptors. 

I went to a friend to borrow some equipment. I removed the old rec/drier
and high side hose, poured about 5oz. of flush into the condensor and
used air pressure to blow it out. I repeated it in the opposite
direction, then used the air till all flush was gone. Cover the end of
the pipe where the flush will exit. Never use flush in the compressor or
through the expansion valve. Now for pressure testing. 
My friend uses nitrogen to test the system before recharging. I
connected the old rec/drier back, hooked up the hoses and slowly put 200
psi of nitrogen into it. sssSSSSSS. One of the new hoses was leaking at
the crimp. New replacement hose is on its way. Its so damn hot, I decide
to put on the old hose. 
Filling with ester oil: I removed the hose connected to the front of the
fuel cooler and pour about 7oz. into the suction side of the compressor.
Needed to turn the compressor over by hand(clockwise) 10 revolutions to
suck in all the oil. I poured about 3oz. into the new rec/drier, then
hooked it up. I double checked all the connections for tightness.
I connected the vac pump and let it pull a vacuum for 2 hrs. to really
dry it out.

Now for the moment of truth. With a good vacuum holding, I connected the
can tap to the charging gauges, screwed in the first can and let 'er
rip. With compressor running, rpm at 1500 and a floor fan in front of
the grill, I monitored pressures. The low side will always go up to
50-75psi at first, but will drop back. Low side, nothing much. High
side, 150psi. Next can. Low side climbing a bit. High side gets to
200psi and drops back. Third 12oz. can. Low side up to about 20-25psi.
High side goes to 275 but drops back. There is 36oz in now, but we need
a bit more. I use part of the fourth can. Amount used was by feeling the
level of coldness on the can and watching the high pressure gauge. Final
was Low side 28. High side 240psi. but will probably go higher in
traffic.

I use the maximum figures of 44oz. of R12. Guidelines are to use 15%
less of R134a. General Motors uses the formula: (R12lbs. X .9)- .25 .
Take your pick. I took the high road and went with almost 39.5oz. of
R134a. High side pressure almost 250psi. I will check it again during
the day and remove a bit if it looks too high. So far so good, and
Adrianne is happy. Personally, I'm underwhelmed by the output of
coldness. Maybe it'll improve. Sources of my info: Two A/C techs and
http://www.delanet.com/~index.htm 
All of the work was done by myself, most of it in my driveway. However,
I was fortunate to be able to borrow the recharging gear from friends.
-- 
Harry & Adrianne
'86 xjs

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