[ST] More Brake Info...

["Nathan Maher" <nate@xxxxxxxxxx>]

Listers,

There's been a lot of discussion about brakes on this list in the past week
(month, year, etc.) and the situation always seems to be somewhat similar, a
spongy feeling lever or reduced feel or control.  One solution that's been
discussed in the past but hasn't come up yet it this round of debate is the
"dirty piston" scenario.  For those who are not familiar with this I'll give
the short version, the brake pistons become dirty over time and stop moving
in a smooth manner - essentially they get stuck.  The solution to this is to
remove the calipers (while still attached to the system) and manually clean
the cylinders.  Stephen McSpadden was kind enough to email me instructions
on how to perform this little operation and given a beautiful Sunday this
past weekend I decided to give it a shot.  The whole operation took a total
of two hours (with a mowing of the lawn thrown in to give the calipers a
chance to fully dry) and really was very simple.  Tools required: a T-55
torx bit, a size 5 metric hex-key/allen-wrench, brake cleaner, plenty of
rags and copper-slip type grease.

Before the cleaning I had a dead spot of about a quarter pull of the brake
lever, that is to say that the brakes did nothing for the first quarter of
the brake lever travel.  When I removed the right caliper only one of the
pistons moved smoothly, after cleaning all four would move with the first
touch of the lever.  The left caliper was only slightly better with two of
the pistons being really stuck and two moving fairly freely.  Again, after
cleaning the pistons all four were moving.  If you'd like detailed
instructions of what I did, let me know, but basically it's no more
complicated than removing the calipers one at a time, removing the pads and
then forcing the pistons to move out so you can clean them.  Care should be
exercised when getting the pistons to move as if they are allowed to come
out to far you can damage the seals and allow air to enter to system along
with spilling brake fluid everywhere.  I'm a hack of a mechanic and I had no
issues so basically if you can open a pickle jar this task is well within
your abilities.

After the cleaning all I can say is WOW!  The brakes feel like they did when
the bike was new - tight, predicable pickup and most importantly, no dead
spot.  I have a feeling that this cleaning will now accompany oil changes
for me as it's just that easy and the results are so good.  I'll report back
if the results do not hold up very long but my sense is that there was some
serious dust build up that wasn't going to clean itself.

Special thanks to Stephen for being kind enough to email me his
instructions.

Keep the rubber side down,

Nate
00SprintRS





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