I need some opinions on brake line size. I'm running drum / drum - Buick 12" fronts (Wilson Welding backing plates) and Ford 11" on the rear (Ford 9" rear axle). I have a drum master cylinder (Chevy '62 pickup clutch / brake combo). So far, so good. I've read conflicting information on the correct brake line size to use on a drum / drum setup like this - 3/16" or 1/4". Any fact based insight appreciated. Thanks.
I used 3/16 all the way for the drum/drum setup in my 1936 Ford Truck. Seems to work ok. Got 2500 miles on it now.
personally i say run the same brake size... 3/16 with a proportioning valve for the rears and your good as gold
The line size does not matter so much, it is pressure that does the work. Yes, you do get a small amount of fluid moving in the line, but 3/16 is fine.