question about my brakes, please help.?

sounds like you have an x-type line system that hasnt been properly blead. a lot of people will follow the regular sequence when bleeding brakes rather tan checking. you know you have a leak somewhere, so that is priobably why your low on fluid and air is getting in makign them spongy and not react. i woudlnt necessarily suggest replacing the line yourself unless your with someone who has some experience, maybe an easier way rather than replacing the entire line would jsut to be cut out the part with the leak and throw in a new BIT of line? (remember to flare it properly or else the leak wil lbe even worse than before if not catastrophic). then make sure you bleed em right:)

Try bleeding the system first.Make sure the master cyl. is full.Start at the passenger rear first, then the drivers side rear,then the passenger front,then the drivers side.Making sure the Cly. is full before you bleed each wheel. Good Luck !

Sort of, it sounds like they need to be blead. (which you will end up doing if you replace the line correctly) If bleeding the breaks dosnt fix it you likely have frozen calipers or possibly a proportioning valve going bad.

You have air in the brake system. Have the breaks bled and look for weeping fluid around the brake cylinders.

50 years fixing brakes and engines.

this could be anything could be a hole in the line could be pinched some how could be low on fluid it also could be the caliper when you push the brake it feels like s sponge could be air in your lines try removing your brakes inspect them bleed brake add fluid look for anything preveting fluid to get to the caliper piston.