It was commented:
> From what I read, when you turn rotors you add to the
> distance a brake pad has to travel to put pressure on the rotor..
If this were true, then the same would be true as the pads themselves
wear.
Disc brake calipers are -self-adjusting' - as need be, the pistons come
out further from the cylinder _and stays there_. All units have some form
of 'pullback' that will retract the piston a fixed amount when pressure is
released. On the Roadster, that's what the metal center post is for.
There's a spring-loaded clamp inside the piston that fits (tightly) over
this post. A spring provides a slight pull back. As the pads wear, the
piston slides out along the post. With pressure, the piston presses the
pad against the rotor. When release, this spring arrangement retracts
the piston just enough to clear a flat rotor.
After a brake job, after you've pushed the pistons back into the bore,
you need to pump the pedal several times before it's firm. That's the
self-adjusting, as the piston comes out to where contact is made.
The problem with over-thin Roadster rotors, besides for heat, is that if
they're too thin (thinner than the center portion of the bridge), the pads
or piston (I'd have to look at which) will push against the bridge and not
the rotor! Firm pedal as the brakes try to stop a solid chunk of metal...
-- John
John F Sandhoff sandhoff@csus.edu Sacramento, CA
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