This is a reply to my mention of Volks Conversions' bolt-on rear-disc kit
for Vanagons. A very useful reply!

Andrew,

In regards to the Sherman disc brake conversion kits it is my opinion that
they are pretty much useless.  I have had one on my 68 beetle and they
provided less stopping power than the drum brakes.  I am studying mechanical
engineering so I did some calculations on the caliper backing plate and
found it to be totally under designed for its purpose.  He makes the caliper
brackets out of a flat piece of Mild steel plate that I found was flexing
and distorting due to the torsional forces created when the brakes are
applied.  This is because the centreline of the brake disc is offset to the
centreline of the caliper bracket mounting position.  The quality of the
brake disc castings is also very poor, I found multiple pinhole
imperfections in mine.  I subsequently found out that John Sherman has no
engineering qualifications, he is a motor mechanic.  After talking to a
number of other people I have also been led to believe that his adaptor
plates are not of the best quality, one guy had his mainshaft needle roller
bearing in his trans destroyed after a month of operation due to
misalignment of the location dowels in the adaptor plate, in other words the
crankshaft centreline and the mainshaft centreline were out of alignment.
I am not trying to put down any of John's products, I am just making
everyone a little more aware.

thanks

David Muir-McCarey
Brisbane, Australia