I keep blowing-out compressor shaft seal

[TimS]

I am having problems and am in need of some advice as to what maybe the problem. I have blown-out two compressor shaft seals while trying to charge the system. From the beginning of the charge it was difficult to add to the system even when it has been evacuated. I tried to add part of the can to the high-side first, but did not seem to want to go in so I started from the low-side port. It was slow to go in but did and at the end of the second can the shaft seal blows-out. The high-side pressure reached a max at about 210psi while the low-side was about 30psi before the seal let go. This has now happened to me twice any help would be appreciated as to what may be the problem.

[Tim]

Not all compressors can just have a seal replaced. If you are getting them seated correctly. Chances are you compressor is shot, and can no longer accept a replacement seal.

[TimS]

Thank you for the quick response and here are some additional details. I have two compressors that have both been professionally rebuilt by a local shop called Austin Rebuilders, Inc.

[Tim]

And what are they telling you the issue is with seals blowing out while charging?

[TimS]

I didn't ask them about why the seals might be blowing-out while charging because at the time I didn't know I had the problem. I replaced the original compressor with a remanufactured one and changed from R-12 to R-134a. After I charged the system it would cool on warm days but shut-off on hot days after running for awhile. A red light would appear on the AC switch indicating that there was a difference in rpms between the crankshaft and compressor that lasted more than 3 seconds. I don't drive the car much so I lived with that condition until this summer when I tried to fix it by adding Freon. The gauges showed the low-side about normal 30psi but the high-side was lower than normal not rising above 150psi. I blew-out the shaft seal the first time. I took both compressors in to be rebuilt and after putting one back in tried to charge and blew the second one.