Apparently this can can have either metric thread or standard SAE thread for the brake line connection.
Without removing the w/c, is there a way to know which I have?

 

Look at the whole rest of the car; like, at the MC. See what size the line nuts are. Cars are all one or the other unless some PO has done somekinda mix & match.

 

If your car is a early '84, it's SAE. A late '84, it's metric. I have no idea when the change was made...

 

car was built in June 1984.
Tkx for the info.

 

I'm guessing it's metric. Of course my guess doesn't really help you as you need to confirm it...

 

Yup, June 84 was the very tail end of 84 production, so it's most likely to be metric. Still, whatever wrench fits on the MC fittings, will tell you right away which one it is, without guessing.

As far as I've been able to tell there's no hard date for the changeover. Seems to have been more gradual. With 2 assembly plants going at the time, and 2 different brake systems, there would have been lots of opportunities for overlap, as the on-hand inventory of various parts was drawn down.

 

What I have done is - I purchased two metric brake fittings with different thread pitches. I do have two old brake fittings from the replaced lines on my 1972 Buick GS (sold).
Come warm weather when I rebuild the rear brake cylinder & replace the brake shoes, I will test the metric fittings for fit at that time.