No brake pedal, at wits end...

[Purplefade]

Ok, here’s what happened...


“OH SHIT – NO BRAKES”, as I blew through that red light and rolled uphill (thank goodness) into the parking lot of firehouse subs where I was able to use the parking brake to get myself stopped. From that point I straightened myself and regrouped for a minute before realizing I had no pedal, at all and no brakes, I could STAND on them and get the X stopped, but I was full into and (maybe) beyond the “emergency circuit”.
Knowing that I was limited to standing on the pedal and anything else that I could do with the parking brake, I set out at a whopping 5 miles an hour home, with my hazards on, giving myself ppllllleeeeeeeeeeennnnttty of space between me and the car in front of me (thank goodness again that it was after dinner and light traffic).



Getting it home I diagnosed no vacuum from the pump and very quickly after that replaced it – to which end I got vacuum at the pump, check valve and booster, but still had no brakes.



Digging in further I was led to the booster, no power assist, would pump up ok with the car off but the instant the car started, straight to the floor, so I replaced the booster, and still no pedal, but the symptoms were different.



With the new booster, the brakes felt great, amazing, but if you sat for any period of time (30\45 seconds) with your foot on the pedal, it SLOWLY sank to the floor, but the car stayed still, however, just slowing down they felt perfect or for just a quick stop at a stop sign where you could see all 4 corners were open they were perfect.



Diagnosing that issue we determined that we had (potentially) nicked the o-ring in the master cylinder during an “aggressive” bleeding procedure and that we needed a new MC.



Replacing the MC, we were re-presented with the vacuum at booster but no power assist that we diagnosed to a failed internal diaphragm and replaced the booster for the second time.



Replacing the booster and re-installing the MC, we were unable to bleed the front brakes, no fluid flow at all, not even a trickle – I have no idea how, but the manufacturer determined that the internal proportioning valve had failed closed on the front circuit… I didn’t even know that was a thing…


So anyway, now with the new, new MC on, I have a total shit pedal, but it is “driveable” and it does “stop” but it isn’t fun to drive and after nearly 3 days of bleeding, again, and again and again and trying a pressure bleeder, followed by a suction bleeder, followed by manually bleeding, I still have a total shit pedal, that stops the car, but renders it almost un-driveable because you don’t really know if it’s going to stop the car. The strangest thing is it takes no foot pressure at all, I mean it’s like magic power assist, I can run the travel out of the pedal to the point where the brakes do begin to engage and they work just like normal brakes, but in less than a single inch of overall travel.



I’m stumped – at this point I’m thinking air, somewhere and have built a recirculation pump to constantly run (not under pressure or sealed) brake fluid from each caliper back to under the level of the brake fluid in the MC so that it can just circulate fluid and let the air come to the surface…
What am I missing here? Many thanks in advance!!

[Happy]

#1. I’m glad you, and everyone around you is ok!

Man..! I hope that doesn’t happen to you ever again.


E53 RiPPeR
XOuTPoST jUNkiE
ReVELaTiON 22:21

[Purplefade]

Thanks Happy!! That was my thought as well, it was literally perfect timing, I was at the intersection with at least 5 cars sitting to my right, waiting for their light to turn green so they could go left. I was just far enough off as it went red to not be able to "hurry through" and when I went for the brakes (which usually stop on a dime (or less)) I had nothing - straight to the floor, didn't even tickle my foot... had I been 3 seconds later (edit: gods honest, probably less) - 3 seconds... their light would have been green and the poor soul who was in front of me at that time would have been right at their drivers door... Someone was sure looking out for someone - for sure!! And the Firehouse subs driveway being uphill, yea, that always happens, it truly was amazing!

[Clavurion]

Did you do the bleeding with diagnostics so pre-charge pump and DSC valves are activated?

[EODguy]

Not 100% sure I remember correctly but I kind of remember that the rod for the booster had piece (clip/spring type) that came off when assembling and caused pedal problems.

I'll try to see if I have any of the old pictures on my old phone.

Sent from my SM-A528B using Tapatalk

[Purplefade]

Originally Posted by Clavurion

Did you do the bleeding with diagnostics so pre-charge pump and DSC valves are activated?

Using my Foxwell NT510... finally gave up and called an indie that I trusted, he couldn't figure it out so he didn't charge me anything (I insisted he take something for his time, he did) and I took it to another guy that I've worked with since I've owned it and they couldn't figure it out either.


The second shop that I took it too got great flow and pressure when bleeding, but when they closed things up and started it the next morning, it was shit again (they did say that the pedal never got "real good" but they did "have it out in traffic and no one died". They bled it again and that pretty much ended me where I am now - HUGE amount of pre-travel followed by just less than an inch of great brake pedal - the ABS still works...


Second shop used both my Foxwell and their "ProTool" to bleed the system and then still went back and did an additional pressure bleed because they couldn't get the pedal up. They weren't quit as nice as the first shop, LOL, they did charge me, but they also did a shit ton of work trying to actually fix it (and it was a very fair #).


The recirc pump I setup shit itself, the little pump I had apparently couldn't handle the head pressure... I am going to get a better pump in the morning and try that again, or just flip to a manual transfer pump and have at it until I pass out - then move on to the next circuit

[Purplefade]

Originally Posted by EODguy

Not 100% sure I remember correctly but I kind of remember that the rod for the booster had piece (clip/spring type) that came off when assembling and caused pedal problems.

I'll try to see if I have any of the old pictures on my old phone.

Sent from my SM-A528B using Tapatalk

Brother, if you told me I had to stand on my head and bleed them naked... I'd almost (almost) send pics to prove I did... I don't remember anything on the \ in the booster at the shaft, I did see the spring clip that retains the MC "plunger" but the OEM and replacement boosters looked like twins inside and out. That said, if you find pics, I'm all eyes, would love to get this sorted. Thanks!

[g300d]

I went through similar with an e46. Did you check the check valve?

It may seem to be "checking" but it may be leaking. I checked it by blowing against it into a container with water. It seemed fine with lots of resistance to my blowing but the bubbles showed otherwise so I replaced the valve along with the vac pump.

[Purplefade]

Originally Posted by g300d

I went through similar with an e46. Did you check the check valve?

It may seem to be "checking" but it may be leaking. I checked it by blowing against it into a container with water. It seemed fine with lots of resistance to my blowing but the bubbles showed otherwise so I replaced the valve along with the vac pump.

Thanks g300d, being proactive, because I had exhausted so many other options, I initially checked the valve and line as good, but somewhere between the next booster and new MC, I replaced that entire line (with check valve) just on posterity... sadly the only difference it made was my wallet $79 lighter...


My initial fluid pump died on me so my recirc idea hasn't come full circle yet, I'm just back with a new pump and getting ready to setup, my hope... is that just letting it cycle through the system in a constant, unsealed loop, will eventually \ finally, push the remainder of any air out.


If this doesn't get me a pedal back, well, I'm not really sure what's next, I've tried to not think that far ahead (for the moment).

[g300d]

Wow, that is frustrating!

Nothing on the scanner about the ABS pump?