Recently I’ve been catching up on maintenance on the Miata. This includes bleeding the hydraulic systems (brakes and clutch). I’ve also had an interment clutch leak which slowly releases the clutch pressure while holding the pedal down (which slowly glazes the clutch by slowly engaging the pressure plate at lights when I think the clutch is fully disengaged.) Because of this I’ve replaced the clutch master and slave cylinder. Each item was $19.99 at AutoZone with no core charge. Replacing both fixed the problem but, I’m sure the slave was the cause of the problem after inspecting it off the car.
Bleeding the hydraulic systems is perhaps one of my least favorite things to do in terms of maintenance because it’s a two person job… typically. Speed bleeders negates the need for a second person; you simply crack the speed bleeder valve, place a catch hose on the expelling port on the valve, and while monitoring the master cylinder fluid level pump the pedal to your hearts content. You’ll notice the pedal gradually get firmer and firmer, at this point your done with that caliper or clutch slave. Russell Performance makes speed bleeders and having used them for about 2 months I think they’re awesome. I haven’t had any issues with them and they bleed right the first time. Typical bleeding the clutch can be a crap shoot and seems to take a couple of bleeds before getting it right despite the bleeding method used. Below is a diagram of Russell Performance’s speed bleeder and some general sales info:
So the parts you’ll need for a 1990 – 1997 Mazda Miata are:
1x bag of 639550 (front)
2x bags of 639570 (rear and clutch)
These bleeders are sold in sets of two, so that’s why you’ll need two bags of 639570; two bleeders for the rear brake calipers and one for the clutch slave cylinder (and you’ll have an extra for a buddy or backup); and then one bag of 639550 for the front brake calipers. I ordered my parts through SummitRacing.com, simply search the part numbers at Summit, should cost about $39.80 for six bleeders and handling charges.
Update: I received an email from a reader who was concerned about the thread size for clutch slave; he suggested that remanufactured clutch slaves used a different thread pattern than OEM. I checked my old clutch slave and new one from AutoZone both use the 639570 (7mm x 1.0) thread.