Mazda Miata Clutch Master and Slave Cylinder Kit with Steel Line

This kit replaces the whole clutch hydraulic circuit on a 1990-2005 Mazda Miata (NA and NB): the firewall-mounted master cylinder with its reservoir, the external slave cylinder that bolts to the side of the transmission, and a stainless braided line to connect them. The master crosses to MC229 and the slave to SC825. Copper crush washers and a bleeder are included.

Miata clutch hydraulics tend to fail in pairs because they are the same age. A master with a bypassing seal gives a pedal that slowly drops or a clutch that drags when the car is hot, and a leaking slave shows up as fluid on the transmission case and a wet boot. Replacing both at once, along with the rubber-to-braided line swap, gives a firmer pedal and a more consistent engagement point.

Signs the clutch hydraulics are failing: the pedal sinks slowly to the floor or stays down, the pedal feels soft or spongy, the reservoir level keeps dropping, fluid is wet on the firewall or under the bellhousing, or it grinds going into gear because the clutch no longer releases all the way. If bleeding brings the pedal back for a day and then it goes soft again, a seal is leaking and the part needs replacing, not more bleeding.

The slave is external on these cars, so this is a driveway job with no transmission removal. Use new crush washers on the banjo fittings, fill with fresh DOT 3 or DOT 4 fluid, and bleed at the slave until no air comes out and the pedal is firm. Check that the master pushrod has a little free play before the pedal starts moving the piston, or the clutch can slip.