Longer stroke to apply them, but lighter touch once they are applied.
Sorry to but in.
Split braking systems were mandated by the fedferal government as a safety
feature in case of hydraulic failure in some part of the brake system.
I suppose the reason they went smaller is that it does not require so much
brake fluid volume to apply the disk brakes since the pads only return
enough to clear the rotor, plus required pedal pressure would be decreased.
Les Myer
At 05:57 PM 10/21/97 UT, you wrote:
>Chris
>
>What it sounds like you are saying is that with all else being equal, the 3/4
>would require a longer stroke than the 7/8 to apply the same pressure. Is this
>is true, does anyone know the bore on the dual line master cylinders? Would
>there be any reason to switch to the dual line other then the dual lines? Does
>anyone know the reason the original switch was made from 7/8 to 3/4? Was it
>because disks required less pressure than the drums to provide the same
>stopping power?, Or did it have something to do with the bore size difference
>between the calipers and the old wheel cylinders?
>
>Larry
>
>
>
>----------
>From: Chris Kotting
>Sent: 21 October, 1997 10:36 AM
>To: 'Larry G. Miller'; Spridgets
>Subject: RE: Master Cylinders
>
>Though I haven't done a conversion (yet), and assuming that I'm following
>this thread correctly, basic principles of hydraulics say you should be OK
>going from the 7/8 bore master cylinder to the 3/4.
>
>I'll try to explain. Let's say you have a small diameter cylinder hooked
>up to a large diameter cylinder, and let's say for convenience that the
>small cylinder is 1" and the large cylinder is 2". You stroke the small
>cylinder 1" by pressing on the brake pedal, exerting a force of 10 pounds.
> The big cylinder will move 1/2", but will exert a force of 20 pounds.
> Half the stroke, twice the force. Larger differences in diameter change
>the ratio upwards.
>
>The MGB calipers have bigger cylinders (also bigger pads) than the Midget
>calipers, hence with the same (7/8") master cylinder, more clamping force
>(and friction surface) on the brake disc, more stopping power for the same
>pedal pressure, at the price of a longer stroke (which might be okay if it
>gives you better "feel"). Going to the smaller (3/4") master cylinder,
>should make this effect more pronounced.
>
>Does any of this make sense, or did I jump a tooth on my mental timing
>chain?
>
>Chris Kotting
>ckotting@iwaynet.net
>
>
>
>
>
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