[V8] Brake master cylinder

[Mark Kalbskopf]

First thing in the morning and when I drive home at night, the first  
couple of pushes on the brake peddle are too hard.
Like the peddle is hitting pressure too high up in its travel.
Then under increased pressure the peddle suddenly drops away and ends  
up in its normal position.
It still brakes OK.  So . . .
I was going to replace the Master Cylinder, but I see it's a whopping  
$300.
Does anyone know if they can be rebuilt with a kit and just replace  
the seals?

Mark.