Dear Tom and Ray:

I'm driving a 1992 Nissan 4x4 pickup, four-cylinder, with roughly 72,000 miles
on it. Recently I've noticed that the clutch pedal has excessive play. I
adjusted the pedal, but found, to my surprise, that early in the morning, when
it's cool out, there is about two inches of play. Strangely, when the car warms
up, or later in the afternoon, there is no free play in the pedal. I decided to
rebuild the clutch master cylinder, and found the fluid in the reservoir to be
very low. I rebuilt the unit, bled the system, refilled the reservoir, and now I
still get the same result. I have several theories: 1) El Nino. 2) The inverse
proportionality between sunspot activity and the breeding time of day of the
dreaded South African Salivating PigDog. In other words, I have no idea. Do you
guys? -- Jay

TOM: Well, I like your theories, Jay. But I would also consider the possibility
that the clutch master cylinder you rebuilt is still causing the problem.

RAY: This sounds like a classic master cylinder problem. Failing master
cylinders -- both brake and clutch master cylinders -- often misbehave when
they're cold and then perform better as they warm up. And that's what yours is
doing -- giving you the proper amount of free play later in the day.

TOM: We never rebuild master cylinders, as a matter of policy. It's just not
worth the risk, in our opinion. It can be done, but there's too much of a chance
that it won't work right. And when you combine that with the fact that for this
vehicle, a new one only costs about $60, it's hardly worth playing around with.

RAY: When master cylinders get old, it's not only the seals that wear out. The
bore itself (the hole through which the piston goes) can also get enlarged and
out-of-round, and the new seals you put in won't do anything to fix that.

TOM: So I'd go out and buy a brand-new clutch master cylinder and put it in. And
if that doesn't fix it, then I'd put my money on the PigDogs.

* * *

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