Replacement A6 compressor for '70 DeVille question

[chrisntam]

Well, it's becoming time to address my leaking front seal on my 2.5 yr old rebuilt compressor.  It's losing oil and Freon (R12) and has been really since I got the car running.

I've called around to all my contacts (locally), no one can replace the front seal.  With that, I'm at the point I'll replace the entire compressor.  I'm leaning very strongly towards using a new A6, made by Four Seasons.  Only problem (that I see) is it comes with 3 ounces of PAG 150 oil, which is to be used with R134.

I spoke to the tech line at Four Seasons, they say, no worries, just drain the oil out of the sump (3 ounces) and replace it with 11 ounces of mineral oil.  Any chance the residual of the PAG 150 mixing with the new oil will have an adverse impact?.

Any concerns with this?  They say there is no way to flush the oil from the compressor other than draining it, which they say is not real easy.

If anyone has recommendations on a good A6, I'm all ears.

[bcroe]

I would call that a failure, seal leaking so soon.  Did you also install new
high density hoses, to better retain the charge?  I would be investigating
if your R12 charge can be saved and put back after the seal repair. 

I would take their advice about draining the oil.  Once the old compressor
is out, it should be possible to replace the seal for a backup.  Bruce Roe

[savemy67]

Hello chrisntam,

You may want to consider replacing the seal yourself.  The following link is a pretty good how-to for the A6 compressor.  I fabbed a seal removal tool from a socket and a 1/2 inch pipe nipple.  Give it a try.

https://www.youtube.com/watch?v=0c7QXLNqgBU

Christopher Winter

[chrisntam]

Thanks for the link, I'll have a look at it.  Only real hurdle for me doing the seal is buying the tools, which it is highly unlikely I'd ever use them again?  Maybe the video will clear up what tools need to be purchased....

On the hoses, they are original, there is no sign of seeping, oil or any wetness around them.  They don't "seem" to be an issue.

I appreciate the responses!

chris.

[V63]

If replacing the compressor...I would also do your hoses. The latest technology in hoses are lined to prevent leakage through the hose body. Also a good idea to replace the associated 'O' rings that connect them. The latest O rings (green) are also more resistant to leaking.


There are hose repair shops that specialize useing your original fittings and crimp on new hose body's custom fit. They are very reasonable.

As an added thought (knowing how hot Dallas can get). I have been replacing the orig condensers with the modern 'cross flow' design. A huge part of effective AC is removing the systems heat. This is done at the condenser. Among others, 1968 Cadillac.  I just did a 1987 Rolls Royce (Harrison system) and it BLOWS (at the vent ) 20 degrees! (See image)

All you do is measure your old condenser (in front of radiator), let's say 16x 14. Then replace with similar size and engineer mounting a little. On 68 Cad I adapted used original mounting brackets. Cross flow Replacement condensers run about $100 on line.

[35-709]

"On the hoses, they are original, there is no sign of seeping, oil or any wetness around them.  They don't "seem" to be an issue."

You may well not see anything "seeping" on your hoses.  The hoses used with R-12 are of a different construction than the "barrier" hoses used for 134a.  The molecular make-up of 134a is different from that of R12 and the R12 hoses will let 134a seep through but not the oil, you won't see any evidence of leaking.  That is why the barrier hoses are used for 134a.

[Dan LeBlanc]

The "new" A6 in the new case won't work on the 1970 as the hoses mount higher up on the compressor body and will hit the air cleaner assembly.  Your factory air cleaner is clearanced for the lines at the rear of the compressor.  If it's a "new" A6 in the original style case. . .of course no issue.

The Pro6Ten locates the hoses in the same location as original dimensionally so you won't have the clearance issue.  I eventually found an end user's photo online where he had the two compressors side by side and it showed the hose connections in the same spot.

[walt chomosh #23510]

Charlie Bryant of Bryant Automotive Air A/C in Tulsa overhauls compressors for a very reasonable price. (they put the compressors under water for front seal leak checks) I've used them a number of times and am 100% pleased with their work and service.....good guys.....walt...tulsa,ok

["Cadillac Kid" Greg Surfas 15364]

Chris,you were right the first t
A new seal and the two r three tools you are going to need to replace it will be far less than a replacement compressor, IF IT IS THE SEAL LEAKING. I just had one (and the first one I have seen) where the compressor body seal was the culprit. The point being, be sure where the leak is. You can use the soap bubble test on everything else but the seal, and if you don't find the leak elsewhere, you were right the first time.
Shaft seals depend upon an oil film to do the actual sealing (between the two surfaces), and to reduce wear.  Most compressors get installed with no thought to pre lubrication by adequate rotation of the compressor shaft and thus activating the oil pump.  They frequently get started dry thus reducing their life expectancy dramatically.  Another quite common cause of leaking is lack of compressor activity for extended periods.  We find this in cars that are not driven on at least a weekly basis with the AC run.
If you don't want to buy the tools you can bring it down here (San Antonio) and I will let you use mine.
Although the new Four Seasons compressor is an excellent piece of machinery and designed for R-134a, I believe it has a 10.? cubic inch displacement vs the 12.6 of the A-6, so you are giving up something on the order of 20% in capacity.
Regarding the oil. I do not know where the "tech" got the oil quantity, but YOUR ENTIRE SYSTEM contains 11-1/2 ounces of oil.  The compressor itself (A-6) has a 5-1/2 ounce capacity.  Pulling the oil plug and draining the oil for an extended period (1 hour) will insure the sump is drained, and the residual oil in the compressor parts should pose no issues when you install Mineral oil.
A lot to think about.
"Barrier Hoses": a subject for another day.
Greg Surfas