92 accord with 143000mi. i noticed that half the time my brake pedal fades to the floor, but half the time they seem to be firm. do i have a bad master cylinder??? or what???

 

Most likely brake master cylinder needs replacement.

 

visually it looks ok (no leaks), but there must be something inside the master cylinder!!!!

 

Brake master cylinders generally are very reliable; but, the most common type of failure is actually internal leak.

 

great. thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1baddturbosi &raquo;</TD></TR><TR><TD CLASS="quote">visually it looks ok (no leaks), but there must be something inside the master cylinder!!!!</TD></TR></TABLE>Yeah. What happens is it leaks back into the reservoir.

 

i just did a full brake flush @ the shop 2 days ago, so all the air is out, but the pedal still fades every couple of brakes & it drives me nuts.

 

it sounds like the cup seals in your master cylinder are bad.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1baddturbosi &raquo;</TD></TR><TR><TD CLASS="quote">... so all the air is out, but the pedal still fades ...
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That's because the problem is bad seals in the master cylinder. Air isn't the problem.