jhummel68

I found the fill valve (993 573 445 00) on the low pressure side is leaking and I need to swap it out. Looking at the parts diagram there doesn't appear to be an o-ring between the fill valve and where it threads into the freon line. Is there some sort of sealant that is supposed to be used or is it a metal-to-metal fit? Second question - Do I need a new desiccator (944 573 143 01) if I have the system open for just a few seconds to replace the fill valve? It was replaced about 2 years ago.

tigerrat

I don't think it is uncommon for the Schrader valve to leak a tiny bit, that's why you should have a quality cap that does have an o-ring seal. My experience anyhow. You could try just replace the valve stem, if that's where it is leaking. Regarding the threads, you could carefully use some teflon tape but someone may have a better idea. If you have the system open just to replace the valve, you shouldn't have to replace the dryer. You will have to evacuate any refrigerant in the system, pull a vacuum and recharge. Ken

jhummel68

Thanks, I plan on replacing the valves and caps. The parts diagram doesn't show anything to seal the shrader valve assembly to the refrigerant line and I didn't see anything in the service manual. I'll take note as I take it apart.

AX993

I'm interested to find out if yours has the schrader type valve or a ball type valve like mine came with (1996).
I had to replace mine with the schrader type because of a leak in one or both of my original ball type valves. Sorry I don't remember if they needed O-rings or not, but I suspect that they did.
Glenn

jhummel68

It looks like the "ball" type. It doesn't look like the schrader valve on a bicycle or car tire. The low pressure side is what is leaking. The piece is very similar to the fitting on a pneumatic hose (quick - disconnect fitting). It appears to be threaded on but I can't see if there is an o-ring or some other sort of gasket to seal the threads.

AX993

Jhummel68, Thanks for info. The ball type must be some sort of euro valve Porsche put on the 993 at the factory. I've not seen them on anything else before, but then again I'm not an A/C tech .