1990 Corsica master cyl which of the four brake lines is one that goes to drivers side rear wheel?

Without a diagram specific to a 1990 Corsica's master cylinder, it's impossible to definitively say which of the four brake lines goes to the driver's side rear wheel. The routing can vary slightly depending on the specific model and even manufacturing variations within the model year.

To find out:

1. Consult a repair manual: A Haynes or Chilton repair manual for your specific year and model of Corsica will have a diagram showing the brake line routing. This is the most reliable method.

2. Trace the lines: Carefully follow the brake lines from the master cylinder. You might need to use a helper to press the brake pedal to help identify which line is under pressure when you press on it. Be extremely careful when working with brake lines. Brake fluid is corrosive and can damage paint and your eyes. Wear safety glasses.

3. Use a pressure gauge: A brake line pressure gauge can help identify the flow to each wheel cylinder. This is a more advanced approach.

Important Safety Note: Working on brakes is serious business. If you are not comfortable working on your car's braking system, take it to a qualified mechanic. A brake failure can have deadly consequences.