I've been having intermittent problems with my brakes since I bought my '76 Eldo. Things have been spongy, squealing, leaking, etc. It seems I correct a problem and things are good for a short while until the next thing pops up.

I've done a new master cylinder, new pads/rotors, new rear caliper.

I recently have replaced my hydroboost unit with a reman unit from cardone. It doesn't match 100%. It seems the functional bits are but the overall size/shape of the spring retainer is different. The studs used had poor quality threads and the original hardware (nuts) didn't fit. I bolted it all up and bled the system. Things seemed to be fine until the pedal went to the floor.

A brake line popped right before the rear driverside tire. Feeling around they all seem a bit rusty. I want to buy a complete pre-bent kit and redo it.

Is this normal when replacing your brake booster that the old lines can't take it? Doesn't make sense to me as the master cylinder diameter really should control the amount of pressure and not the brake booster. I'm guessing its just time for lines.

Is OPG the place to go for a replacement line set?

What are the benefits or drawbacks of going stainless instead of steel?

What other things should I replace while I'm practically redoing the entire system?

PS autozone can keep their $60 core charge. I'm keeping my original bendix unit on the shelf just in case.