Brake bleeding issue

If you are using a pressure bleeder, there is no need to do anything as far as bench bleeding. If, when using the pressure bleeder, you are getting fluid with no bubbles at each brake fitting, there is no air in the system. If the brakes aren't working, and all lines/fittings are OK (not leaking), the MC has failed.

Re brake lines, a fairly common failure occurs when the flexible lines deteriorate over time. But the failure mode is not USUALLY related to your symptoms. It can cause the brakes (typically only one brake but can be more) to lock up after applying and not release. It can even cause the brakes to lock up on their own under certain conditions. I SUPPOSE, though I have not seen it, that the deterioration could obstruct the flow of fluid in the application direction... BUT this problem is unrelated since your getting a soft pedal which is pretty much an air in the system or a MC failure mode.

 

I have had a 355 where I bleed all the four with a Motive pressure bleeder at 15 psi and still have soft pedal. Then I bled the bleeder nipple at the master cylinder and it firmed up. So I have seen the limitation of the pressure bleeder.

 

My experience is that if you have a soft pedal that holds you’ve got air, if you have a pedal that sinks (whether soft or hard) then you’ve got a bad MC seal.

 

If the master cylinder is good and you still can't bleed out the air, be aware that the front calipers can be mounted on the wrong wheel with the brake bleeding ports on the bottom rather than the top. Bleeding out the air becomes impossible.

 

Very common and not just on 355 or even Ferrari for that matter. Part of the reason when they build cars they do not bleed the brakes the way we do.

 

Agree with that, and apologize for not being clear re the pressure bleeder: ALL bleeder screws in the system have to be bled as part of the process, including any bleeds on the MC...