3/4 Ton rear brake line size...3/16 or 1/4???

[FLYNAVY30]

I thought I remembered reading somewhere that the rear lines are 1/4 inch? Im doing the rear disc conversion and while the supplied flexible brake hoses fit the new calipers just fine, I need to cut the factory hard line that went to the drums back about 3 inches and then flare it with a fitting that fits the new flex lines and want to make sure I get this right the first time since I'm sure this will be a PITA with the line still on the truck.

Thanks for the help!

[RManson]

Rear lines are most likely 1/4-inch as the truck had drum brakes originally. Yes, you could get away with using the stock line and making it work with the flex hoses. Ideally, the lines should be 3/16-inch for disc systems, typically speaking.

[FLYNAVY30]

Thanks! Yes the plan is to eventually use the proper proportioning valve, and run 3/16 line all the way back to the rears, but at the moment, I just need to get the truck drivable so I can work the bugs out of the LS1/4L60E swap....both rear wheel cylinders started leaking while the trucks been down over the past year, and I couldn't see rebuilding the drums when I planned to swap to discs all along.

[Stocker]

Just to confirm -- stock rear lines (drums) are 1/4" and front (disc) are 3/16".

[FLYNAVY30]

perfect, thanks! I think the problem is that the flex lines that came with the calipers have a 3/16 inlet