Re: What about my AC high pressure cut of switch?

["Harold McElraft" <hmcelraft@xxxx>]

Not all cars came equipped with the high-pressure valve. That's why 
the manual shows two different setups. It just never got completely 
updated. On later cars the high-pressure switch was located at the 
front of the car at the bottom fitting of the condenser. If you look 
on page M:18:19 you will find where the wiring diagram picks up the 
high pressure switch. It is basically spliced into the wiring (one 
wire) ahead of the low pressure switch. If your car does not have 
one, it is fairly straight forward to put one in. It is a good 
safety device especially with the R134 higher pressures.

It is the low pressure switch mounted on the accumulator that cycles 
the clutch. There are two accumulator types. One, the early type, 
has the return at the bottom of the accumulator; the other newer 
type is higher up on the side. To switch to the later type, which is 
most certainly required unless you can find a NOS one somewhere, an 
adapter for the return hose is needed - or a hose modification or 
hose replacement. I've tried to figure out a rerouting but it is a 
waste of time. Generally you can thread the hoses down the frame if 
you a can get on a four-point lift and use a little ingenuity in how 
you angle things. I have replaced mine without loosening the body 
from the frame.

Since it worked last summer then stopped - you put in a new charge 
and it worked for a while - you DO have a leak. I agree with other 
observations that it is probably the high side hose - but, did you 
check the condenser under pressure? They are notorious for springing 
leaks if the have been damaged by rocks, etc. Also, the evaporator 
can spring leaks because of corrosion on the outside of it. This 
damage can be caused by what I call "being put away wet". I like to 
run the fan at high speed of a few minutes before I put the D away 
for more than a few days because the moisture just sits there 
otherwise and does its damage. Also, the new seals are a must with 
R134 and not a bad idea with R12.

What about the compressor shaft seal?

Harold McElraft - 3354 (high and low pressure switches)


--- In dmcnews@xxxxxxxxxxxxxxx, Michiel Böhmer <michiel.bohmer@xxxx> 
wrote:
> Dear list-members,
> 
> I'm lost here. I have AC troubles and I can't find my answers in 
the archive. I have had my system converted to 134a by a specialised 
company. (new compressor, new orrifice, new accumulator, flushed 
etc.) by the book I would say. It worked for over a year and then 
all of a sudden it stopped cooling after getting very cold.