[TR] TR4 Brakes

[Michael Marr]

  If I partially apply the handbrake, to the point of 'snugging' the wheel
before setting the adjuster, I don't see how, when the handbrake is off, I
have then affected piston travel.


Brian:

The rear brakes work by moving the top ends of the shoes away from each other,
against the drum.  The lower ends of the shoes are held against a fulcrum, by
the springs, which is adjustable by means of the brake adjuster.  Thus, when
the adjuster is turned inwards, the lower fulcrum points move apart so that
the lower ends of the shoes are closer to the drums, thereby taking up wear.
The handbrake lever acts on the top of the shoes and is interposed between the
brake piston and the leading shoe.  If you partially apply the handbrake
before adjusting the brakes, you have taken up some of the brake shoe travel
which would normally be taken up by the adjustment.  Thus, when the hand brake
is released, the shoes will relax to a position further away from the drum
than they were when you adjusted them.

Having said all that, the fact that the rear brakes are adjusted by moving
only the fulcrum point and not by moving both ends of the shoe closer to the
drum means that the difference in the two methods of adjusting may not be
easily discernible, but there definitely is a difference.

I have owned many LBCs over the years and the brake adjusting instructions for
every one of them starts with the admonishment to release the handbrake.

Mike