Recently had transmission issues where the clutch pedal would not hold hydraulic pressure. Led me to believe it was my clutch slave cylinder next to the transmission. I pulled it today to have a look at it while waiting for the new unit to arrive tomorrow. I was able to slide the piston out of the bore. Inside, it's essentially three pieces; a piston, an 0-ring gasket (it's actually cone shaped) and a spring. I've read there are rebuild kits for the slave cylinders. But looking at my supposedly bad unit, there's no fluid leaking past the the gasket. I'm wondering how the pressure is bypassing through the slave cylinder? It's dry on the outside. If it were to go bad, wouldn't it leak fluid past the piston? I'm running a 929 Master cylinder with an AP big brake kit. Brakes work fine.

Also, anyone know if there are other model/year slave cylinders which work with the third gen? Miata, T2?

 

I don't think that they have to be leaking or anything to need a replacement. When my slave went, there was no fluid leaking or anything. I pulled it out and it looked perfectly fine. But, all my problems were solved after I replaced it . Also, I've heard that the rebuild kits do not last long.

 

Ok cool. Affirmation is always good :-) Mazda will have one for me tomorrow.

 

michel,
when mine went bad it looked fine also. no leaks or anything. i switched to the FEED big slave and it works alot better with my clutch setup. also i dont know how many miles you have but i would get a clutch fork also. after i put my new slave in i broke the fork draining the line. so i had to drop the tranny twice in a row. new fork form malloy was like $68 shipped or something like that.

 

Might also be the clutch master cylinder. Typically when clutch hydraulics go, they all go at the same time.

Yeah, definitely get a new Mazda part. Or, see if your city has any parts shops that specializes in imports. We have a shop locally that actually STOCKS the master cylinder, slave, etc. They sell brand-new Tokico parts, who is the manufacturer of the hydraulics. Their prices have always been good - never really compared to Mazda prices.

Dale

 

I'm with dcfc3s. How do you know it isn't the master cylinder? Leaks on that can be hard to see unless you get right up under the dashboard and visualize the cylinder and piston.

 

Correct me if I'm wrong, but I looked and crawled underneath the car and the hood. There's the clutch slave which is attached to the transmission and then there's the the master cylinder with the attached resovoir. There's no clutch master cylinder that I can see...I'd also see issues with the brake system if it was the master cylinder wouldn't I?

 

yea, the master cylinder they are talking about is up under where the cruise control box sits....not sure if that is just for the clutch or not but john and i heard it goes bad too.

 

Just went out and looked...found it! Can't believe I missed it. Lets just hope I ordered the right part. Guess it's a 50/50 chance!

 

yea michel i changed the clutch slave, clutch line, clutch fork and the master. if harrison didnt use my extra new master you could probably buy it from him. i bought two thinking one was bad but it was the fork that was toast.

 

Using a 929 master cylinder now so it wouldn't work anyway. But thanks for the offer! Have any pics of that FEED slave? The new part should be here tomorrow morning.

It'd be interesting to see how many people have slave cylinder failures who are running ACT pressure plates (or other heavy spring plates).

 

nope sorry i dont have any pics of it anymore... i could always take some but that seems like an awful lot of work for something that looks the same except for the numbers on the casing. it made my 6puck with the extreme plate easier to drive thou.

 

My clutch pedal wasnt holding pressure either. I bought a new clutch master cylinder and it fixed my problem. Changing it was a piece of cake. It took me longer to find my deep 12mm socket than it took for me to change the master cylinder.

 

Wan,
You changed the clutch master cylinder, located below the cruise control, correct? And your clutch pedal wasn't holding pressure? So the symtoms for both are identical. Lovely. I actually asked an "expert" before ordering the slave and he never even mentioned the clutch master cylinder. I always assumed there was just a master cylinder and the slave cylinder down by the clutch. I would have ordered both at the same time just to make sure. Argh!

 

Yea, I would lose pressure just by lightly resting my foot on the clutch pedal. It was VERY annoying ( i started a thread on my problem a few days ago ) while trying to pull out of a parking spot or trying to parallel park. My pedal would feel like I had a crazy aftermarket clutch, the kind that engage if you think about moving your foot, making it very easy to stall the car. Replacing the master cylinder, under the cruise control, solved my problem.

 

I did not switch out my fork when I went to ACT xt kit (at 90K). About 3000 miles later I lost the fork and went ahead and replaced master/slave, stainless clutch line, and did a full fluid flush.

I think if you are doing a car with 60K plus go ahead and do them all at the same time. Much easier and cheaper than dropping the transmission twice. Oh and I wont skip the fork again - what a pain.

 

I replaced the slave cylinder next to the transmission...didn't work. Knowing I can't get a clutch master cylinder until tomorrow or the next day, I found a rebuild kit at the auto parts store around the corner. With four simple pieces swapped, the master cylinder is now working again. I didn't even have to disconnect it fully. PITA getting to the bolts. They're 13mm and are on either side of the clutch actuator rod. You access them inside the passenger's compartment. John, I know you mentioned having a hard time bleeding everything. I had no such issues. Simply loosened the slave cylinder bleeder valve and went at it. Took me about 10 minutes. I plan on ordering another OEM clutch master cylinder and replacing the rebuild unit asap. But this'll hopefully get me through the next hurricane :-) I've had a braided clutch line for years so I'm solid there.

I did not replace the clutch fork. I had no desire to drop the tranny at this time. One thing I always do is put the car in neutral at stoplights and keep the clutch engaged until it's absolutely necessary. Keeping the pedal pressed during stoplights probably doesn't do it any good, especially with the ACT Extreme pressure plate. I have 90K on her now.