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Re: [ST] Another testimonial, brake fix seems to work!



From: "Chris" <strizver2@xxxxxxxxx>

> Another thing that I'm wondering is what the heck pushes the pads back
when
> their one the bike??? When you pump the brakes and the pads touch, you
> literally must pry them apart. Why don't they just lock onto the disk when
> you pull the lever?

Well, the rubber dust boots are what pulls the pads back. :-) That's why the
procedure works. The boots seal to the piston to keep the dust out. In doing
so, they stick a bit to the pistons, always returning them to the same
position. The pads eventually wear enough for this to be noticed. Shoving
the pistons back and forth breaks that seal, allowing the boots to reseat
with the pad in light contact. The brakes will also adjust themselves when
the stroke becomes long enough to overcome the boots' elasticity and
stiction.

Just as there isn't anything to retract the pads, (dust boots aside) there
isn't anything pushing them into the disc after you release the lever. Small
irregularities on the discs push the pads back.

The mushy feel isn't all bad. It just means the pads retracted far enough to
be noticed when you brake. Retracting the pads clear of the disc means
minutely better mileage and efficiency.

And now that we're talking about it, I recall clearly the fronts' eyeball
popping effectiveness when I first picked up the bike. I also distinctly
remember hearing the pads drag while paddling backwards out of the garage
the first few days.

For myself, it doesn't make much of a difference. I'd save the effort for
the brake inspection and service before track sessions. Touring use far
dominates sportie use in the flatlands surrounding Chicago. And even so, it
isn't so much a concern for efficiency that keeps me from doing it. The
procedure is just too involved for the daily inspection.

In answer to your other question about lagging pistons: The distance moved
is very, very small. Once the pads are in contact, squeezing the lever only
applies more pressure to the pads. The braking pressure (force, actually) on
the piston is in the hundreds of pounds. The few ounces difference on the
lagging piston isn't noticeable.

And, yes, if it wasn't clear from the above: the effect is only temporary.



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