[e36] [m3] how do I know if I need to rebuild my calipers ?

["George Kofman" <sdg2@xxxxxxxxxx>]

I have 33Kon my M3, and as my previous posts indicate it has seen 4 track
days...   then one evening last week, while swaping pads and being devoured
by our state birds (mosquitoes), I noticed a color change (wetness?) around
the rubber piston seal (LF and RF).  this "color change" appears to indicate
that the seal could be slowly leaking, or I may have over-reacted in my
diagnosis.   sooooooooo, my questions are:

1) what does this "color change" indicate ? is the piston seal leaking brake
fluid ?  I see no tell-tale stains on the garage floor.....
2) if the answer in #1 is "yes, you are leaking brake fluid," then why does
this happen ?
3) how frequently does one need to "rebuild" calipers and what is all
involved ?
4) is ANY of this considered warranty on a car w/ less than 33K on the clock
?

GMK
'97 M3 sedan  (Go Badgers !)

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