Ok to use the old brake lines with new discs?

I've installed a disc kit from ECI on the front of my 50 Chevy, and put a 81 Trans Am disc rear on the back. I was wondering, is it ok to still use the old steel brake lines that are original to the car? They still end under the driver's side floor board where the old MC used to be, but I thought that if they were able to be re-used, then I would only have to worry about going from the flange at the back where the steel line ends and do the lines directly to the rear end, and also run it from where the old MC used to be up to the new power brake ***embly on the firewall. Any thoughts?

Thanks!!

 

been there done that, there could be a whole bunch of problems reusing them, moisture, debris or just overall dirty, (in my case it was debris, somehow I could not clean them well enough) with what the lines cost if you buy them in pieces, you're better off replacing them, especially if you got new stuff up front, you have the patterns already, just buy bend and install.

There are 3 things you do not skimp on brakes, brakes, and brakes.

 

Yeah, the dirt/moisture thing was my lingering concern. I was also wanting to take advantage of where the line clips are currently mounted to the car...which is on the p***enger side...cruddy thing is, the fitting mount on the rear end was designed to have the line run down the driver's side I guess I'll be putting new ones of those in, too. Any idea what they're actually called? Couldn't find anything in an interwebs search.

THANKS!!!

 

The other 3 things you don't skimp on are steering, steering, steering.

Any car can be made to go fast, but steering and brakes are what keeps you alive.

 

I changed all of mine. seems you have to since the original master cylinder has just one line coming out and T's in a few spots. this setup won't work with discs since the fronts need to be seperate from the rears

 

oh yeah, almost forgot steering....

 

From prior experience if it was my vehicle I'd replace the rubber lines and all the steel lines.
Are you using residual valves?

 

Mine isn't going to be a screamer...I put a slightly freshened up 283 in it I'm going with the stock steering for now.

I'm using residual valves and an adjustable proportioning valve. Using one 2lb residual on front, one on back...pretty much this setup:

 

Is the proportioning valve in that diagram needed just because of the weight transfer? I always thought you shouldn't put a prop valve in if you go with 4 wheel discs.