I have been installing a hydraulic handbrake for the last couple of weeks... took a week and many attempts to bleed it... still doesn't work.
Very annoying. Either it still has air in the system though the foot brake feels completely normal... or I got the wrong size master cylinders,
too big. It's a twin cylinder unit in order to keep the diagonal redundancy.
I don't think it's the firewall flex as the sponginess is present even when lightly pressing the brake pedal... and there is always quite a bit of
travel before it firms up. Compared to my BP5 pedal that is rock solid an practically no travel at all.
Could be related to the relative work done by mechanical leverage verses the booster?
The whiteline units are extremely expensive for what they are... but bnt have much cheaper versions... you just need to put better bushes in them from what I hear. And then the weak point becomes the arb mount.