When you install a new drum or a new set of brakes, you'll need to tighten
up the adjustment via the adjustment window on the backing plate.  Once
adjusted, the automatic system (backing up and braking) will cause the
racheting device to "automatically" adjust the brakes.  However, if the
cable or other necessary components are bound up (with brake dust or rust)
or if the rachet wheel is damaged (by an over zealous screw driver) the
auto adjust won't work.  Check the adjustment every six months, or if your
pedal starts going further towards the floor.  Since you're fronts are disc
brakes, when you gain pedal travel (brakes working less effectively) it's a
sign of one of two things, the rears are out of adjustment or you have
water or air in the brake system.

----------
> From: Scott Maurer <smaur@worldnet.att.net>
> To: Multiple recipients of list <vanagon@lenti.med.umn.edu>
> Subject: self-adjusting brakes?
> Date: Wednesday, November 27, 1996 12:03 AM
> 
> I replaced the rear brake shoes on my '84 Vanagon GL.  The Bently manual
> says they will self adjust and not to adjust the emergency brake linkage
> until they do (I think).
> A mechanic with VW said they won't self adjust, that you have to manually
> adjust them through the backing plate adjusting hole. He said not to
adjust
> the emergency brake linkage, the brake shoe adjustment will take up the
> slack.  I attempted this but seem to have had each turn returned by the
self
> adjusting spring and lever.
> 
> I searched the archives and found discussion of self adjusting by driving
in
> reverse and braking hard? 
> 
> I'm concerned about driving without an emergency brake.  When replacing
the
> brake shoes, I shifted the wheel cylinder piston and some fluid leaked
from
> one side. I hope this was because I pushed the piston out too far and not
a
> failing wheel cylinder?
> 
> Thanks,
> 
> Scott Maurer
> '84 Vanagon GL