I have a 1987 740 that I bought this Spring. It was still the old R12
system and all I knew was that the system had no charge, the hose from
the Drier to the Compressor was rubbed thin, and the previous owner
only knew he had a "hole in one of the hoses."
I spent like $120 from FCP Groton to buy an R134 conversion kit. I
spent the extra $20 for an automatic expansion valve (provides better
cooling) and I picked up a hose for $30. I also paid $10 for a complete
O-ring kit.
I went to AutoZone and used their free loaner program for a vacuum pump
and hoses. When I was ready, I made sure my system was completely
de-pressurized (I didn't release any freon into the air, I knew it had
all leaked out, but used a tire pressure gauge on the drier to be
sure).
>From there I removed the drier and plugged the lines to prevent
moisture/debris from entering lines.
I pulled the condensor and flushed it with A/C flush and compressed
air. I pulled the compressor (do not flush this) and emptied the old
oil out and refilled it with the entire bottle of new oil from the
conversion kit. (6.5 ounces I think). Don't put oil in the drier if you
fill the compressor.
I re-installed the compressor and condensor with new O-rings, put in
the new expansion valve, replaced my bad hose and used new O-rings, and
finally installed my new drier last. Install the drier last to prevent
unnecessary exposure to air. The drier is chemically lined.
Once everything was re-assembled with new O-rings, I pulled a vacuum
for 1.5 hours. I then filled the system with 3.2 cans of standard R134
and she has been working well for the last month since I've done the
work.
I wish I would have flushed the evaporator, but people have mixed
opinions on the need.
Here is the guide I used:
http://www.volvoclub.org.uk/faq/VolvoR134Conversion/R134ConversionPage1.htm
Jamie
> > First thing to check is the charge, try bypassing the pressostat on the
> > receiver/dryer, if the compressor kicks in then check the pressure.
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>
> John