911 brake pedal softness on track days

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cobra98 - 15 Nov 2006 07:08 GMT

Have new discs, pads, braided steel lines, best fluid, and they're
pressure bled. After five laps pedal is soft, and will sink in pits. OK if I
have a nervous pump before braking zone, but I think there is a better way.
Any thoughts?Mastercylinder? It's a very fast 1993 964, ABS and tiptronic
(and better than you think!)

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Ed Beroset - 15 Nov 2006 11:22 GMT

> Have new discs, pads, braided steel lines, best fluid, and they're
> pressure bled. After five laps pedal is soft, and will sink in pits. OK if I
> have a nervous pump before braking zone, but I think there is a better way.
> Any thoughts?Mastercylinder? It's a very fast 1993 964, ABS and tiptronic
> (and better than you think!)

If you don't have any external leaks, that sounds like either master
cylinder or the fluid is boiling. I'd bet on the latter if you only
experience this on the track. You also might want to try manually
bleeding the fluid before your next track event to make sure that there
really isn't any air in there. As I'm sure you know, even the smallest
bit of air in the lines makes a difference.

Ed

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oreely - 24 Nov 2006 10:34 GMT

boiling fluid, A little bit too hard, too late.

>> Have new discs, pads, braided steel lines, best fluid, and they're
>> pressure bled. After five laps pedal is soft, and will sink in pits. OK
[quoted text clipped - 10 lines]
>
> Ed

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