bleeding a C4's brakes - why need a pressure bleeder?
 

Ok, call me ingnorant, but while reading the section on C4 brake bleeding in Adrian's book, it mentions the use of a Power Bleeder to pressurize the hydraulic system. Why, if the pump is being activated to pressurize the system, does a pressure bleeder even need to be used?

It seems that the hydraulic pump would do the same thing as the pressure bleeder - no? Therefore, I could just pressurize the system, then open bleeder screws; no?

So, if I indeed need the bleeder, is there a certain "model" of the Motiv bleeder that's needed so I know it will fit? For years, bleeding my 65's system was done with my foot on the pedal (or my wife's!).

;)

The C4 is more enjoyable when it's not in this state(!!):

Please go back and read the book again. The hydraulic pump has nothing directly to do with applying pressure fluid to the brake callipers. The hydraulic pump is for the assistance for you to use the brake pedal and supplies pressure fluid to PDAS when activated.
You cannot pump the pedal because without hydraulic boost you cannot move the pedal unless you use both feet.
You can use the hydraulic pump to bleed the accumulator and the dual solenoid block but this takes special care.
Ciao,
Adrian
964C4

Using your pedal is not the right way, you could damage your internal cylinder seals because they enter a corrosion zone inside your cylinder. Normally you never let your pedal reach that far.

Ah-ha! That's right Adrian, thanks for the reminder. For some reason I was thinking it pressurized the entire system, versus "assisting" the master cylinder - of course that would make no sense, then the calipers would be squeezing the brake pads all the time!!!

Thanks for the clarification/reminder, Adrian. I appreciate it as always!!

Now which Motiv model do I need?! :)