[Healeys] Rear breaks locking

[Chris Dimmock]

Hi Alan,
You'll end up taking off more than 1/8 inch off a shoe that is fully  
lined, but if you reduce the lining by small increments you won't  
stuff them up. I'll try and find some old original shoes and give you  
a closer shoe length.
Unless someone else has a spare set of old rear shoes available they  
can measure and post the answer here.
Chris
www.myaustinhealey.com


Sent from my iPhone

On 20/10/2010, at 2:27 AM, Alan Bromfield <bluehealey at gmail.com> wrote:

> Brilliant!! Exactly where my thought processes were going.
>
> On my BJ8 this problem was particularly prevalent with the rears  
> locking up far too easily.  I thought it was caused by weight  
> transfer to the front under heavy braking.  I discovered soon after  
> that my apparently perfect Vredestein tyres were abut 10 years old  
> and had the consistency (and grip) of wood!  New Michelin XAS  
> helped, but the over braking of the rears was still a problem.
>
> Reducing the swept area of the shoes will reduce the efficiency,  
> raise the temperature, and should give a better pedal feel around  
> the max braking point.  I've never tried it but figured it was worth  
> some research.
>
> Tell me does just 1/8" off the trailing edges really make a  
> noticeable difference?  Would leading edge be more effective by  
> reducing the servo effect?
>
> Just exploring before I get in there with the hacksaw.
>
> Cheers.
>
> On 19 October 2010 14:18, Chris Dimmock <austin.healey at gmail.com>  
> wrote:
> Hi Magnus,
> The main reason I've found for rear brakes locking is that most  
> modern rear brake shoes are relined across the entire shoe.
> Standard Healey shoes in the era were never relined over the entire  
> metal shoe surface. NEVER.
> Hence more rear braking capacity.
> <Snip>
> Rear brake shoe lining size adjustment is the way that many race car  
> drivers have adjusted rear brake bias long before adjustable bias  
> systems came along. And still do in classes of racing that prevent  
> the adjustment of things that weren't adjustable.
> <Snip>
> Conceptually. Just use a hacksaw to cut the lining to reduce the  
> surface contact area, until the rear brakes no longer lock first.  
> i.e. Just reduce the lining surface area!!!
> <Snip>
> The process:
> Break really hard like your kid ran out in front of your Healey, IN  
> A SAFE PLACE - well away from other people/ cars/ children. Full  
> emergency brake.    Just test to see if you have rear lock up.
> If you do...
> Jack up and cut 1/8 in off both rear linings.
> Start at the trailing edge.
> Retest. Repeat.
> <Snip>
> Until it no longer locks at the rear.
> <Snip>
> It's not rocket surgery. But it is time consuming.
> Chris