<VV> Brake problem fixed and new brakes

[Frank DuVal]

Yes, when the drum is larger than the specification calls for, the 
circumference of the drum is larger than the circumference of the shoes 
so unless you beat the shoes into a new shape, they will only touch the 
drum in the center of their arc. I once worked on a 67 VW that had a WAY 
oversized front drum. The shoes showed contact of only two inches, and 
of course they were worn to the metal. This is a one year only front 
drum assembly, but I did find a replacement at the time.

This is why (and I do expect to start another early/late, hot/cold 
argument) I never turn a drum unless there is an obvious problem 
(grooves, out of round, etc). Why throw out good metal when the surface 
is fine? Sure, Corvair drums are easy to come by NOW, but other cars I 
have are a lot harder to find parts for.

Frank DuVal

Mark Edmonds wrote:

> 
>Last summer (2007) at NECC Lime Rock time trials I had the left front brake
>fade at the end of the main straight as I started my second timed lap.
>After that it pulled hard to the right every time I braked.  
>On the street it pulled to the right very slightly every once in a while,
>and only for a fraction of a second just as braking started. 
>I had put new shoes on in 2006 when I first put the car on the road, and I
>replaced the wheel cylinders in spring 2007.  This past winter I decided to
>replace the shoes with Kevlar shoes, replace the hardware and have the drums
>turned.  
> 
>I found that three of the drums would be out of specs if turned again, and
>the front left drum was already out of specs.  In looking at the shoes and
>drum carefully it appears that because the radius of the drum was larger
>than the radius of the shoe, there was not uniform pressure on the entire
>shoe, thus under extreme conditions that wheel could not brake as hard as
>the others, plus the portion rubbing the hardest probably got hot quickly.
>My conclusion is that this is what caused my braking problem.
>
>  
>