87 4kq clutch master cylinder

[William Murin <murinw@cs.uwp.edu>]

Colleagues:

My q with its new clutch developed an interresting malady yesterday.  #2 
son was driving the car.  Push clutch pedal to floor and it stays there.  
Alternatively, push pedal to floor, and on the slow return back up it 
decides (all by itself) to go back down to the floor.

Mechanic who keeps the car running says his best guess is that the clutch 
master cylinder is going bad.

Is this a reasonable diagnosis given the symptoms as described?  The car 
has 157,000 miles on it and it is the original master cylinder.

What is anyone's best guess as to the price of a new one?  rebuilt?

Thanks--as usual


Bill Murin