Ive been trying to nip this problem for months. It pulses and is extremely soft on the pedal. It has a new master cylinder, new wheel cylinders, new rotors, new pads and I’ve tried flushing it 3 times but still no luck. Does anyone have any suggestions?
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Would just have to work with it. May have air in lines, may be not using good protocol to get it flushed out? Maybe leak? I recommend walking thrtough each line individually with a pal in driver’s seat who can apply slow, firm, even pressure to brake, flush each line taking care that you get each one to feel solid (no air).
Sigh. I was thinking about replacing the brake bleeder screws. When I use the vacuum there are an immense amount of bubbles. When I just let it drain I get micro bubbles. I can find any leaks.
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Sounds like a leak for sure. Do you know which line it is on? If no, we just need to get it up with wheels off so we can play with it. If you do that part, I’m willing to try to help.
Warning, I am computer guy, not mechanic, but Ive gotten lucky and fixed few car things lately. Seems car and computers both conform to logic and laws of physics.
Care to set up give it one more look?
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Same here. I’m a computer guy and shade tree mechanic.
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Well then, lets render a shade tree, maybe even put an auto with possible air leaks in the brakes beneath.
We can augment our already inflated egos and pretend to fix the problem. Then render artificial celebration once we have it all figured out.
I’m game. Just let me know when. I’ll bring artificial friends. Even loyal ones. 
I’m wondering if I should just some brake line and try to replace them
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Well you have replaced everything else… lol…
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If new lines does not make it happen, I might look into a new foot, or maybe even a new driver altogether…
If you let me know when you will be up there to set up, I’ll bring a driver with feet that have been fully tested. To be specific, these feet have two decades of rigorous testing, and passed all relevant testing. They have for sure never seen three or especially not four decades of testing. It is two. Two decades of testing, and that is all.
What kind of car/brakes is helpful information.
“Pulsing” pedal is usually caused by warped rotors/drums.
“Soft pedal” should be further defined by “pumps up” or “always soft”. “Always soft” is usually an adjustment issue. “Pumps up” is usually air in the lines. Vacuum bleeders suck. 
Sorry. Could not resist. But seriously, vacuum bleeders are fine, but not my choice. Good old fashioned pump’n’hold with a helper is best if you can’t get your hands on a pressure bleeder. If you replaced the master cylinder, it should have been bench bled. Some cars (usually Chevy/Ford/Dodge) seem to NEVER bleed properly if you didn’t bench the m/c.
Why replace brake lines? They are not likely at all to cause air in the system. Fluid out of the system will be far more noticeable. If you’re not finding fluid leaking out, lines are not likely the problem.
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Unless they are bulging. That’s another thing to look for when someone is pressing the pedal.
It pulses softly and is always soft and it brakes but only when the pedal is on the floor and it brakes hard at the floor when it suddenly catches.
You replaced the master cylinder, but did you check/replace the vacuum booster?
Also, there may be another piece for ABS in there. Is it throwing any codes/check engine light on?
No check engine light and I haven’t checked or replaced the vaccuum booster. No codes.
Those would be brake hoses. Brake lines are hard, and made of steel. They do not bulge.
Brake hoses may be made of rubber, and might bulge. Although that seems self-explanatory, you are absolutely right: if you spot a bulging brake hose, replace it; a helper might make that easier.
Depending on age, condition, operation status, etc. replacing brake hoses as precaution may be a good idea, and much different proposition than replacing brake lines.
hmm…
This sounds like a “Please show me” situation. I’m not sure what “pulses softly” means.
Again knowing more about the setup might help.
From the description it sounds like a bad primary chamber on the master cylinder, as suddenly catching at the floor would be caused by the primary chamber bottoming out, and then building pressure on the secondary via mechanical action. This could be checked by having a helper press the pedal whilst checking each wheel to see what their action is during braking.
Knowing more about the car (make/model/trim) might help with other ideas/suggestions.
I’ll throw this out there, too, as it has proven somewhat helpful in my past: you can “gravity bleed” the system, too. Keep the brake fluid reservoir full. Open each bleed screw, and let the fluid drain by gravity action. Set up a catch for the fluid, and go have a cup of coffee, some lunch, etc. Just make sure the reservoir does not run dry, and cycle through each wheel in turn. There are some systems this works better on than others (pickup trucks, for example, don’t work very well, as there is effectively zero brake fluid flow to the rear wheels when they’re unloaded)…
Thanks. Near the floor right before it catches it sometimes pushes upward for a second.
Armoured:
You said you replaced the shoes and wheel cylinders - tell me how you adjusted the shoes after you installed them?
Per Jast - if you haven’t bled the master cylinder yet - you should start with adjusting the shoes and bleeding the M.Cyl.
Year make and model would be helpful.
Bleed screws do not fail in service. Hardlines don’t either - unless from rust or poor servicing practices.
Flexible hoses last a long time but as Raymond posted - inspect for the “usual” suspects in a rubber hose, bulges, cracks, separation, leaks, etc.
I prefer the 2 person brake bleed over the vacuum anyday.
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What I did was attach the shoes to the contact points and using the auto adjustors screw tried to adjust for a bit of resistance. I think I need to just start from scratch and bleed them. I did get some new brake bleeder screws for 5 bucks just in case. I do definitely need help. My wife isn’t tall enough to feed the master while bleeding it.
