Mazda Repair: clutch problem, mazda miata, manual clutch

Question
I have a Mazda Miata M5 with a manual clutch problem.  I didnt recognize the occasional "tough to get in gear" problem for many months because it didnt happen all the time - very infrequent.  Then, all of a sudden I cant get it in and out of gear, nearly not getting home.  I notice the fluid is at the low marker and fill it.  No improvement.  No petal resistance at all.  It will shift in and out of gear with the motor turned off.  Someone suggested pumping the clutch - that seemed to help the petal (that time).  Someone suggested that I may just have air in the line and that it may be self bleeding.  Since it was now shifting smoothly again, I took a hours drive and the first half hour shifted constantly over and over through all gears.  Only a few times did it resist or stick, when it did I pumped the clutch (which seemed a normal petal) and it shifted fine again.  After an hours drive it refused to shift into a new gear and shortly after that I felt the petal pressure disappear when I was holding it in and no matter how I pumped it it would not engage nor did the pressure reappear.  Is this air in the line?  Will it bleed itself?  Or something else?  Since the manual transmission has no dipstick I have not checked the oil level in it - could that effect the clutch?  And...just because a computer compensates for everything, I will mention that at the same time this all happened I started having cylinder missing at low RPMs (starts fine), could this be a clue?  Do I dare drive it an hour to the nearest mechanic without doing damage?

Answer
Your experiencing clutch hydraulic system failure.  The master cylinder and the slave cylinder are due up for replacement.  Once done your good to go for another 30-40k.  Use new parts not rebuilds.  Mazda or Beck Arnley offer good new parts.  Roughly $300 parts and labor.

The rubber pistons within the cylinders wear and can either leak pressure internally or leak fluid outwardly, either way the two parts wear at comparable rates so replacement of the pair is our proper common practice.

The M5 manual transmission should be serviced every 50-60k, we use Valvoline Full Synthetic gear oil 75w-90.  It has an over flow design that does not use a dipstick.  On the driver side of the gear case is an over flow plug the fluid is filled until it appears at this plug then it is re-sealed.  If there are no outward signs of gear fluid loss then there is no reason to believe it will be low.

The low speed misfire is not related.  (I don't know which year you have) Ignition wires and spark plugs should be changed every 35-40k to keep the Miata ignition system operating at peak performance and efficiency (use NGK plugs and NGK or Racing Beat wires.  You are experiencing an ignition break down where and insufficient amount of spark energy is reaching it's destination, the system may have the ability to overcome the resistance at higher RPM's and also at higher RPM's a misfire is less pronounced in effect.

service@miatashop.com