Ok so I was cruising down the highway today around 70mph going about 15 over the limit when i passed a cop I downshifted to 4th gear then put it in neutral to cruise down to the speed limit I then pushed the clutch back in the put it in 5th and felt a pop in my clutch pedal and it went straight to the floor. Could not put the car in any gear and I coasted to the shoulder.

ALL BEARINGS AND CLUTCH PARTS HAVE 23k miles on them. It's an ACT Extreme Organic clutch and has been working flawlessly until today.

Now I checked the slave cylinder it appears to be moving just fine (minus the stiff pedal pressure) and I am not leaking any clutch fluids. Turn the car off the car shifts just fine I was able to put it in first gear then start the car and drive onto an off ramp but could not shift the car once started.

It doesn't make any weird noises at all when started or driving or when it stopped working i just felt a pop in the pedal that was it.

Any ideas as to what might have happened before I decide to pull my transmission? What happens when a Clutch Master Cylinder fails?

 

Sounds like a destroyed throwout bearing...

 

But wouldn't that make noise?

 

Not necessarily. I had one pretty much disintegrate on me.

 

DAMN! not what I wanted to hear. lol

 

Just have to break it apart and see what you find. Sorry for your loss

 

imo before you crack it apart have someone actuate the clutch while you watch the movement. but yeah odds are it is TOB or the fork that drives it. The pop you felt gives me hope that this is indeed a hydraulic problem.

 

I don't know about hydraulics, the pop you describe makes it sound like something actually broke.

 

It kinda sounds like hydraulics. But, assuming that there's fluid in the master and the pedal works normally (as, the pedal operation is only dependent on the hydraulics), you may have to take off the tranny to see what's up.
However, if the pedal simply sinks to the floor, you got hydraulics issues. Either master or slave. (yes, you CAN have busted master and NOT leak any fluid).

 

UPDATE: Something def broke, didn't actually have time to pull the tranny today but I put the car up on ramps and pulled the shift fork boot off as I noticed the fork had some abnormal play in it mainly up and down and in and out play that my friends miata does not have. Jiggled the fork and this metal thing came out. I think something on the fork itself broke, going to try and get the transmission pulled here in the next day or two.

Like I said Clutch and bearings only have 23k miles on them but the Transmission and Fork itself have 273k miles.

I am pretty sure this is the clutch fork pivot ball?

 

Well finally pulled the transmission today and the only thing that broke was the FORK PIVOT BALL an $8 part, Im glad its so cheap but sucks that I had to pull the transmission to replace it.

 

That sucks, but at least you didn't have to wait on a new clutch.

 

my friend broke that pivot ball several times on his FWD BP.

apparently the MSP has a more durable pivot ball, not sure if it will work on a miata trans though.

 

Wow. I have never seen a failure like that. Usually these only need to be replaced because of wear on the ball itself. Cool that its cheap to fix though.

 

Yeah I have looked everywhere for any kind of failure like this on a miata and only thing I can chalk it up to is high mileage just kinda wore down over time. Just hope the rest of my transmission isn't planning the same thing.