I have found the leak in the AC system on my "91 RS (V6). There is a pressure switch in the back of the compressor. The O-ring on this switch needs to be replaced. I have tried a couple of O-rings with no luck. I need the dimensions of the correct o-ring. Where can I find the correct dimensions I.D., O.D., thickness?

 

As long as you're going to have the system open on a 23 year old car, why not buy a whole seal kit for it and ward off future problems?
http://www.ebay.com/sch/i.html?_trks...at=0&_from=R40

 

OK if I get the kit, how do I know which one fits where?

 

Remove and compare is how I did it.

 

I've already done that and failed 2 times. I'm looking for exact dimensions or part numbers. Thanks

 

I had this same problem.so I went and got o rings with varying thicknesses and used the fattest one I could wiggle in there.problem solved

 

If you're still running the stock R4 compressor and I'm assuming you're looking for the o-ring for the high pressure switch, you should be able to find the o-ring you need here:

http://www.rockauto.com/catalog/x,ca...parttype,13290

If this doesn't work for you, you might want to put on your "humble" cap and drop by your local A/C shop with your switch (and the old o-ring if you still have it) and ask them if they have an o-ring that will fit.

 

I did that too just yesterday, had the kit, did a remove and compare. The system took the charge and seems to be holding but now my 25 year old compressor is not engaging like it did last year. I just posted about it too.