[Healeys] Bad Brakes - Now Good Brakes

[Ray Juncal]

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
Healeys at autox.team.net
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