Kim,

    If your sure there are no external leaks in the systems, lines, wheel
cylinders, calipers, etc. Then the master cylinder is "by-passing", (leaking
internally) and needs replacing or rebuilding.
    I would replace it with a new unit, (kind of pricey) rather then using a
rebuilt or rebuilding yours. The reason being, your cylinder bore may be
worn out of round, or pitted, etc.
    But if you must use a rebuilt unit, buy from a good re-builder. As they
will use a new housing or re-bore the one they rebuild. So saving a few
bucks on a "Brand X" re-builder, or rebuilding a worn housing is false
savings and will catch you in the end..............so to speak! ;-)
    Have a good one.

Howard

Subject: Squish...

When I brake, if I'm lightly braking,
> the pedal slowly sinks to the floor. I don't notice it sinking if I
> suddenly hit the brakes, or it I pump the brakes.
>
> No leaks at the wheels. Fluid level doesn't seem to be falling. So