Thank you.
After swapping o-rings; the vacuum leak is slower but still there. I was incorrect that I needed the 5/8in and 5/16 in sizes for the expansion valve. Those two sizes were if the expansion valve was removed from the AC piping that goes to the compressor. I suspect that I need the proper o-ring for the expansion valve to seal the leak since I do not have any sizes that fit like the older o-rings I removed.
So it seems that I need the larger sized o-rings that goes into the evaporator core. However, no o-ring is listed for sale on the online parts store, so I assume that the o-rings come with either a new expansion valve or new evaporator core. I purchased a new expansion valve and hope that it will be sent with new o-rings.
Hyundai uses very thick(fat) OEM green o-rings than what most
aftermarket companies sell. The
aftermarket o-rings will fit the pipping, but they are not thick enough to seal. It seems like the factory spec o-rings are the best way to go to seal this leak up.
Unfortunately, I lost the original expansion valve o-rings. One was lost on removal and the other got tossed out. I did not think it would this hard to replace them.