Hi guys

I recently got an 87 IROC. It has the rear disc option. Now the break lines are mostly shot, and by that I mean the rear discs do nothing due to a leak in the lines. (I can still stop fine though I have to keep putting fluid in every so often).
I plan to redo the lines to the rear brakes.

I tried to do this on a 91 firebird I owned and had to give up due to the way the rear lines are designed.
Im assuming here that the rear lines are the same design as for drums and that they differ from where the metal line merges to the rubber pressure line to the rear brakes themselves.

From looking at the lines they seem to be a consistant diameter until they taper down and bend to hook into the bracket that secures and connects them to the rubber pressure hose.

On the 91 not only was this also the case but the fitting for the rear line to the rubber pressure hose was unique to that specific location of the brake system.

Running the line is no problem. Im wondering what to do about the line taper and the smaller fitting that I am suspecting is unique like I said. Im also pretty sure I cannot reuse my fitting since it is quite rusted. Is it ok and possible to convert it all to a standard break line size like 3/8 diameter or so.

Id like to plan this out as Id hate to do it and have to cap the lines to the rear off at the master cylinder like I had to for the 91.

Thanks for any help