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Old 12-11-2012, 02:36 AM
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Originally Posted by boothboy View Post
Here's one for you brake guys.

Will worn rotors cause a low pedal? I'm not talking about warped or scored rotors, I'm talking about the rotor thickness dimension being reduced. I'm not talking about a soft pedal, I'm talking about a low pedal.
What do you think?
In some cases, yes. The square cross section rubber seal between the piston and caliper acts as a return for the piston/pads by deforming when the piston is extended then returning to its normal state when the piston is no longer held extended by fluid pressure. This gives a running clearance, but if the rotor thickness were less, the pads could still retract as though the rotors were normal thickness. This is one reason that new pads often have shims w/them.

Because the caliper fluid volume is relatively large, any extra clearance between the piston/pad and the rotor translates into an increase in pedal travel.
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