2013 Audi A8L 3.0 Air introduced into Master Cylinder

Hey everyone I don't have any DTC errors but would be willing to post a full scan if requested without any issues.
I'll start from the top with my issues and procedures.
I had my light come on saying replace brakes so I purchased my brake pads and noticed the light was on because of a brake wear sensor being broke. At this point I said I'll replace the pads anyways because they had about 6 months or so left. So after replacing everything I love doing the Gravity bleed because it has never failed me. I raised my car on my lift and removed all Bleeder screws from the Calipers and made sure master cylinder was full. This is where it gets fun, Long story short I had an emergency with my chid and completely forgot about my car . Yes I ran the Master cylinder dry I believe, I then filled everything up and this time waited by the car while doing it. This didn't help at all with a completely soft pedal, I then had the wife pump the brakes and I bleed them in the sequence stated in erWin. Still no luck, I then used my Vacuum bleeding again nothing, I then used my Mitivac and again same thing. The only thing I can think of now is to remove the master Cylinder and bench bleed it and then do the normal brake bleeding sequence. My questions is am I forgetting something? Any thoughts? I'm worried I may have introduced air into the ABS system . I do see there is a brake bleeding option is 03-Basic Settings with 3 different sequences to select from but I didn't want to mess around with that without more guidance. Please help me out I'm not a complete professional but most of you know I won't give up and will do what he is told like a good boy . Thanks!!!! BTW I have been doing the bleeding for about 2 days now I will have it sent to s shop if I really need to but I would like to do things on my own.

Have you tried a reverse push bleed at caliper directly & where you inject fluid into the caliper, then extract fluid at tank on master cylinder?

This is how we do it on planes as per FAA and MIL spec requirements.

Most good mighty vac tester kits support this function.

Jack@European_Parts said:

Have you tried a reverse push bleed at caliper directly & where you inject fluid into the caliper, then extract fluid at tank on master cylinder?

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Hey Jack, I have not tried that unfortunately I don’t have anything to force push fluid into the calipers to make this happen.

Does your mighty vac support a push, if not maybe get one?

Jack@European_Parts said:

Does your mighty vac support a push, if not maybe get one?

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Unfortunately it only sucks, I purchased it to do oil changes lol. I could get one, I’ll have to check if there is a local retail store or order on Amazon. I was hoping to get it up and going ASAP as my job requires a lot of driving lol. I assume not to use the option bleed brakes in 03?

Well you could remove a line at master and add a line into fluid container at one caliper per time and one by one suck it too, no?

Jack@European_Parts said:

Well you could remove a line at master and add a line into fluid container at one caliper per time and one by one suck it too, no?

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So to confirm your saying remove one line from the master cylinder and cover the hole on the master cylinder. Then put the line into a bin full of brake fluid, at the time use my vacuum bleeder at each caliper? If so this will also get the air out of the master cylinder? Also this would do the trick right?

Phoenix Systems (2104-B) V-5 Reverse Brake Bleeder, Light Duty One Person, Fits all makes and models

Did I instruct, I was merely asking questions, you should always follow the RTFB, right?

If you removed lines at master you could affectively bench bleed master at same time & while placing bleeder caps on each line and bleeders closed at each respective caliper to prevent gravity right?

Jack@European_Parts said:

Did I instruct, I was merely asking questions, you should always follow the RTFB, right?

If you removed lines at master you could affectively bench bleed master at same time & while placing bleeder caps on each line and bleeders closed at each respective caliper to prevent gravity right?

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Sorry for Assuming you was instructing me. I'll ask this instead, If I purchased this Phoenix Systems (2104-B) V-5 Reverse Brake Bleeder right now. Would This in theory bleed the whole brake system? I assume it should because Pushing fluid in reverse as you stated and the air is popping out of the master cylinder top. Would this be a fair assumption? As always thanks for your help.

Some questions the answers are indeed self evident huh?
Is this the mechanical repair section of the forum?
Who are you better yet who am I?

Hey Jack, I'm going to purchase the Phoenix system now and pray it get's me out of the weeds, I'm hoping I didn't introduce air into the ABS system. I'll leave an update on my findings once I get the system. Jack I know your a busy man, I know your here to help and not give the answers to educate people this is me assuming again of corse.. I want to thank you for your quick responses...

Sometimes good questions make you think, I wonder what this means?

BostonSlaya said:

I'm going to purchase the Phoenix system now and pray it get's me out of the weeds...

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Ironically, my pressure bleeder is a $5 weedsprayer

Seriously - I made a fitting to go on the master cylinder cap, from a spare cap; for pressure bleeding after the ABS swap on my Touran. I imagine it would work just as well backwards, screwed into the calliper bleed. I just wouldn't trust it to have fluid left in it, but so far, the hose that came with it has lasted for well over a year, and I've used it 4 or 5 times now, sometimes at high pressure and no brake fluid explosions...

Do you still use brake fluid as weed killer?

Jack@European_Parts said:

Do you still use brake fluid as weed killer?

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I'm sure it will Work!!! lol My reverse bleeder just showed up tonight!

Jack@European_Parts said:

Do you still use brake fluid as weed killer?

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I did drop a tub of it a while back, and it was more effective than Roundup!

So did a reverse bleed on all 4 calipers and still the pedal is the same. I ordered the master cylinder because I didn’t find any leaks in the lines at all so it has to be the MC. Anyways I’ll update once complete

Did you take MC apart and look for sludge from gravity fun ingress, burr or damaged bore causing the issue from being dry and see if you could save it with tanking/cleaning, light hone, pre-lube & a bench bleed?

Possibly shit from bottom of tank entered bore?