'93 Sedan Deville retrofitting issue

I Have a 1993 Cadillac Sedan Deville and I just tried to retrofit the a/c valves for R 134 charging. But unfortunately I was unable to retrofit the low pressure side because the fitting would not fit on the low pressure valve.

Do Cadillacs require you to take them to the dealer for special refitting or perhaps a conversion for R 134?

I used a kit that was purchased at Wal Mart that had all of the fittings needed, I am wondering if you purchased the correct one?. KC

Well, the fittings that I bought came from Autozone. I told the parts man that I needed a low-pressure fitting and he went back and gave me a set of high and low-side fittings because they don't sell them in singles and didn't ask me what kind of car I had so I just assumed that they were universal.

When I screwed the low-pressure fitting on, after a few turns, I heard the gas hissing out. So apparantly, the core in the fitting was too long to screw in the valve.