Clutch cylinders

It is possible for the clutch slave to let air in without a visible leak. Clutch slave cylinders are a frequent source of problems in Miatas. You should probably change yours.

Thanks for the reply Natman. I reckon even if it isn't the slave cyl. it'd b a good idea to change/repair it since it's been neglected and the fluid was black with sludge on the bottom of the res. R rebuild kits easily found and is the savings worth the xtra work or should I just replace the cyl. How much would I save doing the kit? Thanks again very much.

I don't know. Mine went suddenly and I couldn't find a kit right away. I'd recommend that you get a new cylinder (not OEM). Then if your original core is still good you can rebuild it at your leisure and have it ready for next time.

Thanks. Apparently, rebuild kits only exist for the MC not the slave and even they r hard to find. Thanks again.

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Wise advice! Clutch slaves are cheap, and even cheaper to rebuild. I do a rebuild on my spare for $6.00 and some tax, shove it in a ziplock bag with one of those silica gel packs, mash all the air out, then shove it in another ziplock and stick it in the glovebox. Seriously! :)

I can usually have it changed within about 10 minutes of jacking up the car. Cheap insurance.

BTW, Nat - I had one go sudden once, with no kit on hand - Found out that a 3/4" drum-brake cylinder cup needs to be *JUST TOUCHED* to a grinding wheel all the way around to make the clutch work *AT LEAST* long enough for the rebuild kit to come in. Without the touch to the grinder, it's just a hair too large, so it gets stuck in the bore after the first time you apply force, holding the clutch out.

Whoever told you that is full of it right up to his eyebrows.

Slave rebuild kits can be had from Autozone, Kragen's, and probably just about anyplace else that does parts - I get mine for about $6 at the local "mom-n-pop" parts place, where they keep 'em in stock. Jerry at the counter says they sell at least 4 a week to the large local "riceboy" population.

Ditto MC rebuild kits, only those are about $11 a pop.

If your parts-critter can't source it for you as a Miata kit, have him try looking for a '79-up 323, 626, or 929, or a 77-ish Ford Courrier kit. They're all the same kit. Several Hondas and Toyotas also use that kit from what I'm told, but I don't know which ones specifically.

My local guy told me that nobody stocks rebuild kits for either the MC or SC. Told me the same thing for a rebuilt alternator I just bought from him for a diff. car I own. I used to rebuild those years ago. He apparently doesn't want to deal with any rebuild kits, more $ for him selling full on replacement units I reckon. I ordered the kit from Trussville that "Lanny" wrote about. Thanks all.

Just to let u all know, I rebuilt the clutch slave cylinder over the weekend and it is working just great now. Clutch engages now, where it should, and not a 1/4" off the floor anymore. Had trouble with the lower mounting bolt, but finally got it off. Used compressed air to remove the old piston, no one had told me I'd have trouble with that. I thought there'd be a circlip to remove and then the spring would push it out, but that wasn't the case. With nothing to grab the piston by, I tried compressed air and that shot it out! Lightly sanded the interior of the bore to remove some rough, rusty spots. Reinstalled and bled using the usual two man method. Also, cleaned out the resevoir while I was at it. Thanks everyone for all your help.

Mine engages about 1/4" from the top, but that's because the clutch is virtaully worn out. The car spent its first 59,000 miles in London...