Clutch Master cylinder leaking

Anyone replace one of these yet? Seems really early at 75,000 miles. I was reading the service Manuel that I downloaded from this site. The clutch pedal assembly has to be removed with the master cylinder as a single unit. Then I can replace the master cylinder. Ok a lot of work but I can deal with that. But before I have to disconnect the steering shaft from the steering gear. Not sure I'm comfortable with that, but I will have to try.
Also says to remove, air cleaner, battery, tray, PCM.

If anyone has done this, just really want to know if the steering shaft has to be disconnected or can I work around that. It just says disconnect. So I assume just to move out of the way

I found these instructions online, same as in the manual

http://www.mcx5.org/clutch_master_cylinder_removal_installation_c66_m_r_-1100.html

The clutch pedal had too much free play. Just had to barely lift the clutch pedal off the floor and I was moving. So I thought maybe some air in the system. Tried to bleed the system and fluid starting leaking into the passenger compartment. Its so bad, I have it parked, not running and it has a slow drip. I have a pan there now to catch it.

Seems like after reading that walkthrough that taking the steering shaft off gives you the clearance you need.

I think you are right. Not sure why Mazda would make such a cheap part that is a lot of work to replace. They used to make them like brake master cylinders. Now just a plastic piece, no wonder is bad already.
Oh well, hopefully the dealer will have one and I can have a busy Sunday.

After reading over the directions again. It says to install a new starter interlock switch, and new clutch pedal position switch. Not sure why I can't reuse the other parts. Can anyone verify if this has to be done?

timberstx said:

After reading over the directions again. It says to install a new starter interlock switch, and new clutch pedal position switch. Not sure why I can't reuse the other parts. Can anyone verify if this has to be done?

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My guess is that dealers probably put in new switches because they don't want to risk them being/going bad after doing an expensive repair and having to charge for the same job a second time. They are probably cheaply made switches.

Yes that might be the case. I ordered the Master cylinder. It will be here on Monday. Im not waiting on the switches. The first thing the directions say in the removal of the clutch pedal assembly is remove the switches. So I f they go bad I can replace them easily.

Edit. I started taking things apart. I took out the Air cleaner ( this will make it easier to get to the slave cylinder to bleed the system when done ).
I took out the battery. I did not take out the Battery tray and PCM component. I don't see why I would have to. I have a clear opening to the Clutch Master Cylinder. I will start just saying CMC. for that. I posted a pic. The CMC is just southwest of the bright red. If anyone can think of a reason to remove the PCM let me know.

Hopefully there will be more shortcuts when I get to the inside of the car.

update again
Inside the car
I disconnected the wiring to both switches and removed the clutch pedal position switch. Left the starter interlock switch in the assembly. Don't think it will hinder the removal of the assembly.

The hardest part was breaking loose the 3 12mm bolts holding the assembly to the firewall. I finally used a 17inch breaker bar on the top left one. Not sure how much torque they used. I will ask when picking up my part tomorrow.
Looks like I have room without disconnecting the steering shaft. But will see tomorrow (don't want to disconnect the hydraulic lines until I am ready to finish the job ). If I have to disconnect, it really doesn't look too bad.

Last update for this repair.
Using the instructions in the link you don't have to do the following.

3. You must remove the Battery, but don't have to remove the PCM or battery tray.

5. I disconnected the electrical but did not removed the switch until the pedal assembly was out of the car. I removed it only so I would not damage it trying to twist the CMC out of the assembly.

6. I did not have to remove the joint cover and don't know what it is.

7. No need to disconnect the Steering shaft. There is room to pull out the pedal assembly.


Symptoms of my CMC going bad was too much pedal free play. And I only had to lift the pedal off the floor a little and the car started to move.

Put some bars leak stop and send it

Chris_Top_Her said:

Put some bars leak stop and send it

Click to expand...

Now you tell me.

timberstx said:

Symptoms of my CMC going bad was too much pedal free play. And I only had to lift the pedal off the floor a little and the car started to move.

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I just had this happen to me overnight (2013, 100k miles). Soft pedal, especially in the first half (aka free play), gears grabbing close to floor. Is CMC all you changed and did it fully fix the problem? Any chance it being the slave cylinder?

Change both the clutch master cylinder and slave cylinder. For whatever reason, the clutch disc is still dragging on the spinning flywheel when the clutch is fully depressed causing the gears to grind. Fix it before you have an expensive transmission repair on top of fixing the clutch. Personally, I hate the sound of a screaming wallet.

Jmaz said:

Change both the clutch master cylinder and slave cylinder. For whatever reason, the clutch disc is still dragging on the spinning flywheel when the clutch is fully depressed causing the gears to grind. Fix it before you have an expensive transmission repair on top of fixing the clutch. Personally, I hate the sound of a screaming wallet.

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Not sure what you are talking about here. May be you misread "grabbing" for "grinding". No noise or slipping in my case.