[Healeys] Bad Brakes - Now Good Brakes

[John Vrugtman]

This site explains it quite well. 
http://science.howstuffworks.com/hydraulic1.htm

On 2/5/2010 2:44 PM, Ray Juncal wrote:
> Tony
>     I think you and I are saying the same thing.  Maybe I am confused about the
> mechanical advantage involved.  If pedal movement is constant the larger slave
> cylinder will move less distance.  Does that equal less force working on the
> brake shoes?  The smaller slave cylinder will move a greater distance and it
> seems to me push harder on the brake shoes.  I am having a hard time getting
> my mind around this and I really want to have a basic understanding of the
> concepts involved here.
>    Here's what started this whole deal.  I have two 100s, one pretty far along
> in resto one in waiting.  When ever I can I rebuild parts for both cars at the
> same time.  One car is stock late BN-1 ( four, one inch front cylinders on
> early narrow drums, two one inch rears with wider hypoid axel drums ) no
> problem here. The other car came to me with BJ-8 front disc brakes and will
> have BN-7 / BJ-8 rear cylinders.  They are 7/8"slide in the backing plate
> single piston cylinders. Can I use the 100 master cylinder with the later
> brakes? The later cars have a brake booster. Do I need to add a brake
> booster?  Could I use a larger or dual master cylinder?  What other options
> come to mind?
> Thanks for your help
> Ray
>
> --- On Thu, 2/4/10, Tony Shope<tonyshope4227 at yahoo.com>  wrote:
>
> From: Tony Shope<tonyshope4227 at yahoo.com>
> Subject: Re: [Healeys] Bad Brakes - Now Good Brakes
> To: "Ray Juncal"<healeyray at yahoo.com>
> Date: Thursday, February 4, 2010, 9:14 PM
>
> I worked in Hydraulics for 40 years,  The larger the cylinders are the greater
> the force.   Area x pressure = force.   also the larger the cylinder the more
> fluid it takes to move the cylinders a set distance so you will require more
> travel of the break pedal .
>
> From: Ray Juncal<healeyray at yahoo.com>
> To: PatrickQuinn<Patrick.Quinn at det.nsw.edu.au>
> Cc: List Healey
>   <healeys at autox.team.net>
> Sent: Sun, January 31, 2010 9:39:13 PM
> Subject: Re: [Healeys] Bad Brakes - Now Good Brakes
>
>
> Patrick
>     I'm not a hydraulic expert myself but I think it's the other way around.
> Smaller diameter wheel cylinders give more pressure for the same pedal
> travel.  Let me know what replies you get.  I very well could be wrong and I
> want to know.
> Regards
> Ray Juncal
>
> --- On Sun, 1/31/10, Quinn, Patrick<Patrick.Quinn at det.nsw.edu.au>  wrote:
> G'day
>
> Perhaps you might recall a few months back I asked for the collective wisdom
> concerning the brakes on the BN3?
>
> I
> Excuse my ignorance of hydraulic science, but I am told that by increasing
> the
> front cylinders from 7/8 inch to 1 inch it will improve the brake performance
> considerably. The brakes are not boosted and the car is fitted with a
> standard
> AH100 brake master cylinder.
>
> Hoo Roo
>
> Patrick Quinn
> Sydney,
>   Australia
> H