Brake line sizes

[orangeGMC]

I already used the search function and am a little confused on the opinions/data from others. I am going to install an adjustable proportioning valve in my truck for the rear disc brakes. I would like to mount it right next to the master cylinder. But I don't know which line is front or rear out of the master cylinder. From what I read different master cylinders switch it front to rear resivoir. Is it the larger line or the smaller line for the rear brakes? And what sizes are those lines? I am also going to remove the stock proportioning valve and just "T" the front lines. Has anyone else done this?

 

[sweetk30]

i did the swap. and 3/16 line for front and 1/4 line for rear. p.s. any of the adj units dont come with the correct 1/4 line adaptors. but i got some at the local napa. i made little bracket and mounted it to the maset with 1 nut for it to the bosster unit. keept it high and dry and easy to adjust .

 

[R72K5]

yeh the larger one is the rear line it splits off to 3/16" at the axle diff housing hose

fronts always 3/16" and stays same all way to the front brakes, drums or discs.

good luck