In regards to the main front-to-rear brake line..... For 1967 Buick switched from a 3/16" diameter brake line (used up to 1966) to a 1/4" line..... The only operating characteristics that would differ, that I can think of, would be the larger line would have a greater volume.... Assuming the same rear wheel cylinders are used, the amount of fluid displaced to operate the brakes would be the same.... The line pressure would be the same .... The only advantage I see is that there would be less flow restriction with the larger line....but I can't see that making much difference. I'm upgrading to front disks on my '66. Should I go with the larger diameter line? Thanks!
If I remember my physics correctly , one of the basic laws of Hydraulics ( I can't remember the guys name) was: all pressure in an enclosed system will be transmitted undiminished throughout the containing vessel. The size of the line will make no difference. The only problem will come when you change wheel cylinder diameters
With larger lines it might take slighly longer to bleed the system, and require a bit more fluid. Other than that, you can use 6" line if you want to (well not really). -Bob Cunningham
So it sounds like it makes no difference...I wonder why GM went to the larger line in 1967....durability perhaps? ....the line may be less likely to be restricted by dents or buildup of corrosion inside the line. o No:
