UPDATE:
I just had an event. I have now replaced:
- Brake master cylinder, brand new
- both front lower control arms with new ball joints
- re-bled ABS w/INPA, tons more bleeding of brakes
To be more clear, the issue is this on track:
- If I pump at least 6-7 times on a long straight AFTER a high-G corner, I get solid pedal that bites up top
- If I pump 2 times or so, or none, I will get a mushy pedal that bites much lower than normal, but still get solid braking.
I'm trying to build muscle memory on these corners but every corner I get varying braking pedal points that I lose confidence on how much brake I am applying. Some corners the pedal is almost to the floor, others it's right up top. Can't win HPDE like this...
If I'm at idle and press the pedal, it goes down a bit, but slowly sinks and sinks till almost bottom. If I pump, it catches up top again, but will again slowly sink.
If I had air in the system, would that mean I would never get a solid pedal no matter how many times I pump?
I've also thought about pad taper, and this may be causing the pads to angle a bit after I press the pedal, thus the reason for it to sink.
Uncharted territory yes, but the odd thing too is when I had my 335i front floating brakes, there was none of this nonesense. Only after going to Stoptechs did this happen.
The only thing left is to move over to Z4M front end, but that will be costly on so many levels. I don't want to go back to floating caliper either.
Video below captures one of the issues I have: