Fox T-Bird/Cougar Forums  

New 3/16" and 1/4" Brake Lines
The 1983-86 Cougars have the stock 3/16" brake lines from the master cylinder to the back, along the passenger side framerail. (On 1987-88 cars, the brake lines ran down the driver's side, and you can simply omit this part). Now Turbo Coupes used 1/4" lines in some parts to handle the higher volume of fluid. However, it is very expensive and impractical to replace all your car's brake lines. Therefore, new lines on the rear axle itself will need to be installed. One side will use the 4' section of 3/16" line (driver's side on '83-86), and the other side will use the 14"; piece of 1/4" line. You will also need a 3/16"-to-1/4" adapter for the longer side, where the line enters the junction for the caliper hose. This is because you will use your stock brake junction; one side is 3/16", the other side is 1/4". I would not recommend using brass adapters, as they will not fit correctly and can leak fluid. Steel adapters work best. You can purchase a line bending tool for about $7 or so; that'll help you get the funky bends you need to jump the center section of the axle. If this all sounds sort of strange, don't worry--it'll become clear to you as you attempt to hook up the brake lines