Those are the classic symptoms of a leaking slave cylinder. Your clutch
itself is probably fine. Replacing or rebuilding the slave cylinder is
easy and inexpensive.

Are you related to the '70's era Chapel Hill Goforth architect/builder? I'm
told I own one of his properties...

dookie

<snip>

Good guess.

About 15 dollars and 15 minutes, plus jack-up and bleed time, is all it
takes to do a Mazda (and a whole lot of others!) RWD clutch slave, even
for a rank amateur. A slow-moving rookie might be able to turn it into
an hour or so job if he wanted to.

Idunno how "wrenchy" you are, so if this is so simplified it comes
across as insulting, my apologies. It's not intended to be.

Get a slave rebuild kit from your local parts joint. While you're there,
grab some extra brake fluid. A quart or two should be plenty, and leave
you enough to top up as needed.

Jack it up and put it on stands, then get underneath. The slave cylinder
should be glaringly obvious. If it's not, your vision and/or lighting is
too poor. Call an optometrist or electrician before proceeding. :)

Break loose the hydraulic line coming from the MC at the slave - Just
crack it. Don't try to completely remove it yet. Trust me on this...

Now undo the two mounting bolts AND THEN, once the slave is dangling by
the hose, rotate the slave to remove the line. The whole slave assembly
falls off into your hand as a convenient unit. Set it aside for now.
(someplace "brake fluid safe")

Using an appropriate container to catch what you're pumping out, pump
the clutch pedal until the MC is empty - You've probably got "yuck" in
the system from the slave rubber deteriorating, and you want to get rid
of it. Don't hesitate to refill the reservoir with clean fluid a couple
of times, as pumping some fresh clean fluid through it can only help
flush the MC and line nice and clean.  

Point the hydraulic fitting of the slave cylinder at your container, and
mash the pushrod that's poking out of the rubber boot to get rid of most
of the fluid in the cylinder, then pull the boot off of the cylinder and
set it and the pushrod that's probably trapped inside it aside.

Use a tiny spritz of compressed air into the hydraulic fitting to pop
the old piston/cup/spring assembly out. You just want to pop it out, not
shoot it across the county :) Inspect (the bore should be nicely smooth.
if it's scored badly, you might need to either hone it, or if it's
really chewed up, get a fresh cylinder), rinse out any "yuck" inside
with clean brake fluid if needed, "grease" the new cup by dunking the
whole spring/cup/piston assembly in clean fluid, and drop it into the
cylinder, spring first, then press it into place, being careful not to
nick the rubber cup.

Replace the boot/pushrod (Depending on who made it, your rebuild kit may
come with a new rod/boot already assembled, or you may have to pull the
old boot off of your old rod, and put the new one on it - it may seem
like an awful tight fit, but it'll go), then, keeping the hydraulic
fitting at the highest point, mash the rod to force out air, and while
pouring a trickle of fluid into the hydraulic fitting, slowly release
pressure on the rod to pre-fill the slave with fluid, repeating until
you don't get much, if any, air out by mashing the rod. (This helps take
most of the hassle out of bleeding later) Set the whole assembly aside
(keep the hydraulic fitting pointing up!) for the moment.

Attach a clear line to the end of the line from the MC, the same way you
would for one-man brake bleeding, and fill the MC. (And keep it filled
throughout this operation!) Now bleed it out - GENTLY!!!!! You've got an
open system, so it won't take much pedal force to give yourself a blast
of brake fluid in the face, or pop the clear line off, forcing you to
start all over again. Keep pumping/filling as needed until the clear
hose you attached is full of fluid and bubble-free.

Now comes the one tricky part - Removing the clear line, and attaching
the hydraulic line to the slave. The idea is to do it as smooth and
quick as possible to minimize air getting trapped inside the system.
Eyeball your options, and do it as best you can. I like to try to do it
from above, but that's just my preference. Turn the slave cylinder, not
the hose. Don't worry about getting it cranked down "final-tight"
(yet...) Just snug it up as best you can.

Once you've finished, cuss real loud 'cause you forgot to put the little
copper washer back on the end of the hose. Pull it apart and put the
washer back on. :)

If you went for the "do it from above" method, feed the slave and hose
back down to where it lives. Otherwise, just bolt it back into place on
the tranny. Crank the hydraulic fitting down solid AFTER you've finished
with the mounting bolts.

Do a final bleed. It shouldn't take much more than a few strokes of the
pedal, since if you've done it even slightly like right, you've already
gotten 90+ percent of the air out in the reassembly process.

Mail me a $50 money order for the consult :)

You should be good to go.

Eric,
Mine did the same thing today. I got it home by  pumping the pedel a lot
just before I was going to use the clutch. I had a slave as a spare that
I had put a $8.50 rebuild kit in so I made the swap about an hour ago. I
have a "speed bleeder" on it so it was a fast job to do. RED is all
better now and ready to go. :-)  I bleed the system twice a year, but
they still go out. It is just one of the things you need to keep up with
on a Miata. Take your old slave and clean it up good with "Alki", get a
rebuild kit, (NAPA has them) use a little bit of brake fluid on the
rubber seal and put it together and seal it up in a good "zip lock" bag
so you will have a replacement for next time (and there will be a next
time!)  NAPA also has the complete replacements too.  

Yes, just about anyone can replace the slave cyl. Removing the Right
front wheel assy. makes it very easy.  Tools: 10mm "tubing" or open-end
wrench.
                   12mm socket wrench (for the
                    hold-down bolts)
Note: besure you start all the bolts and tube nut with your fingers so
as not to "cross-thread" any of them!!!

     Bruce     RED    '91