Master Cylinder Physics

enkeivette

Well-known member
Joined
Mar 30, 2008
Messages
990
If a stock C3 master cylinder is a 1.125" bore. A stock C5 master is a 1" bore... Isn't that a step back?

I understand the booster provides assist only, and so upgrading the booster does nothing for pressure effectively.

And with the same pushrod actuation it seems that a C5 master would produce slightly less hydraulic psi per inch.

So, is upgrading braking force really just a matter of better calipers and larger diameter rotors?
 
I'm even wondering if I should be searching for maybe a Chevy truck master with a larger bore, to up the psi in an effort to mimic the C6 setup a bit better.


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line pressure is a result of MC bore size and force applied (factor in pedal ratio, assist and leg pressure)

A 1" master needs more travel but less pressure, simple hydraulics rule. Why would that be a step back?

Modulation is what you want, not tip touch locking brakes (hence hydroboost is junk IMO)
 
IF there was, say a recurring engine design failure that was exhibiting the kind of crap I have endured on the shitty brakes on my '72, I would have set fire/claimed insurance and walked away, but with the improvements and basically nowhere to go with the brakes, I stuck it out....the stock vacuum booster never showed any defect...even on tear down, held vacuum, all rubber seemed fine valve was good, just that it took a month to stop the freek CAR due to pedal travel....tried large diameter m/cyl helped a bit, but still frustrating in local traffic with these idiots here....

I replaced that 'prop valve' which is nothing but a pressure diff. switch between front/rear....and for some reason that seemed to help a little bit, mainly in the fluid consumption....showed some evidence of leaking from the switch ports...but never any diffenitive evidence.....

then Hydroboot with some consteration on my part.....did not touch the truck m/cyl plumbing just pulled it off the booster, and changed for the HB unit... Pulled Sharkey out and pushed the brakes going up hill, and sharkey stood on his nose and banged my nose into the wheel......

went to an aluminum Pirate Jack Racing m/cyl with screw on aluminum cast top.....standard bore for the car..... brakes stop great now....

it is true that I had some brakes problems since then....bad hose on left front, burnt up a set of brakes.....later on put in new rotors/pads.....for some stupid reason the rotors wore on the inside diameter of the INSIDE of the surface, and cocked the pistons over in the SS bores.....killed the 'new' rotors, I suspect CHINA on the castings so put on some old stock rotors I forgot about in back of the storage room....and new pads, fine for over a year now, no signs of shit going on.....

BUT, when I punch the pedal, the car STOPS for a change!!!!


Vacuum sux......


:pprrtt:

bolted in place,
 
If you go with a larger diameter bore, it will INCREASE the amount of pedal effort required and require a shorter stroke; a smaller bore will DECREASE the pedal effort, but require a longer stroke.

Here's are really neat way to add assist mechanically-

P1010014.jpg
 
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