Brake Line Size/Flare for 1st gen W-bodies?

[GranPrix]

I have a 95 grand prix sedan and have read on some sites that these cars use bubble flares and on others that they use double flares.. Which is it? If some lines are double, and some lines are bubble, does anyone know which lines are double flared?

Also im assuming that the line size is 3/16 but not sure on that either.

I am replacing two of my rear brake lines that go into the rubber line and I want to get the right size brake line and flare type before I change out the line, so I dont accidentally get the wrong size line and have to go back into town. 

When i replaced brake lines on my Buick Park avenue they were bubble flare, but not sure if W-bodies have the same flare type

[55trucker]

In a word.......both

the flex hoses at all corners are ISO to the chassis bracket, if memory serves the rear brake lines unions (2) under the car near the fuel pump filter are SAE, the master cylinders are ISO.

You'll need both an SAE double flaring kit & an ISO flaring kit.

Replacing the right rear brake line is no pic-nic, the line is run over the top of the leaf spring fastened in 2 places to the suspension sub frame (right where it rots out). You cannot see the line as it is placed just to the forward side of center of the spring. One cannot get their hands in there to maneuver as there is no space.