Failling brakes after repeatedly bleeding brakes i still have very little to no presure. how can i tell if i have a leak in the lines? HELP !!!!

There is 3 ways of bleeding brakes that can help get all the air out.
1st is the pump and open. start at any side and keep the reservoir full pump and open the nipple until there is no splattering when you bleed, 2nd is to use an adapter that fits on the reservoir and this applies pressure so you only open the nipple and keep it open untill you see clear fluid flowing through it. 3rd way is my fav. you have a container that's airtight with 2 hoses running from it, one connected to nipple and another to a large syringe, you open nipple and pull on syringe until the fluid is clear.

all basics....
longest to shortest order. just look at lines you can see where they go in 5min.
rusted or leaking or crushed lines are bad. super basics.
damaged, no , only the bleed valves were touched and yes they do break, and for sure in salt belt. (wiki that)
its needs bleeding,
if the MC and slaves (all parts) dont leak there is air in the system.
if all air is out (i use pressure bleeding) but if all out, then the MC is bad.
spongy is always air , bleed again, repeat.
get a book on brakes, see how to do bleeding 6 ways.
some ways are better, or like me I use 3 ways.
keep in mind , air wants to float up, and tell me which way are you using... 2man way? opposite of the float rule?
sure. its classic way and can be very hard.

-Double check. No leaking....?
-If not leaking. When you bleed it. you might need some one to help you pump the brake.
-Make sure Pump the brake (Hole down still)/Now open or release the fluid and Closed BEFORE release the brake pedal. Repeat this until no bubble. And make sure the fluid reservoir never empty to Bottom.
You should be good to go.

Mai

Open the bleeder on the caliper and take the cap of the master cylinder and let it sit for a few minutes. If still you get no fluid out try opening the metal line where it does into the rubber line and see if fluid comes out there. If so you have a bad brake hose which is common. If you still dont get any try to have someone help you bleed it. Mean having someone sit in it and you open the caliper bleeder and tell them to press down on the brake pedal and hold it. When they have the pedal on the floor you close the bleeder. Repeat this several times until fluid is coming out of the bleeder. After you have fluid coming out, have them pump the brake pedal 3 or 4 time and on the last pump keep presure on the brake. Take a min now and check your brake fluid level, running out would kinda be a pain. Now open the bleeder and allow the brake pedal to sink to the floor of the car. Ask the helper to tell you when the pedal is on the floor and not moving anymore and then, while they are still holding it down close the bleeder. I would do that again once more and then remember to re check your fluid level in the master cylinder.

Check the rear wheel cylinders? Was anything leaking at the master cylinder? Does it have ABS?
Check the front caliper slides are free. Check the front caliper pistons for leaks as well. This is all assuming you bled the brakes(all 4 wheels) properly after all that replacement! You're getting air from somewhere for sure or if it has ABS, the pump may have a problem.

did you bench bleed the master cylinder before putting it on car. if not there is air in braking system. you can try this, have someone pump the brakes and hold them. when loosening line the brakes will go to floor, tell person to hold them till line is retightened. loosen one brake line to get trapped air out. close line and have person pump then hold the brakes and repeat above till the brakes go to floor. if this does not get all air out! then bleed at wheels. ( how to bench bleed master cylinder ).----- put in vise, fill resovoir full of brake fluid. use a dowel or similar to pump master cylinder,pump untill fluid is free of air bubbles shoots out that has no more air in it. keep fluid in it or you will get more air in it. when putting on car have fluid in it. as long as you do not loose fluid from lines, you should be ok!! have a good holiday !! if all else fails. be sure there is no leaks at the wheels or brake lines. usually if a wheel cylinder is leaking. you will see this on inside of wheels on backing plate. be sure to fill fluid when done.

if you are losing peddle and their are no leaks in the system, meaning you have to keep adding fluid then you have an internal leak in the master cylinder . if it was just air in the lines, not bleed right you would have a spongey peddle meaning it would stop but the peddle would feel like rubber, or it would pull to one side

You changed the master cylinder and vacuum booster and have no leaks anywhere, but did you bleed the entire brake system after you did this work? A little bit of air in any of the lines will make the brakes ineffective.

you need to hold in the metering valve.when you bleed the front brakes.long as the valve closed off you wont be able to bleed front brakes.better to get extra help.hard to bleed by your self .

first you must fill brake master cylinder star the engine get someone who can go in side the car to pump brake pedel keep puming check the how is the brake flude going through the pipes fil again if it not full tell him to keep down and hold brake pedal now you bleading the system front side have look the niple when you relese the presure close then tell him to keep pedeling keep going several times tell him to keep and hold the bedel down relese the pressure again, close fill the brake fluide finish front side like that way come rear wheel do same like front.
check any leaking.

sorry my english