CSC or CMC problem?
 

I've done some research and it sounds like I might have one of these issues. These past couple weeks my clutch has felt different. Sometimes It'll feel like there isn't much pressure when I press down on the clutch. But that's ONLY after running it hard. Normal driving it's completely fine. So last night I ran it hard and right after I stopped and I tried pressing down on the clutch and it wasn't engaging!! It didn't want to go in any gears. I pumped the clutch with my foot and it eventually engaged into gear again and pressure came back and I drove normal the way home and it drove fine again. I think I might just need to change my clutch fluid or do I have a part that's on the edge of failing?

Kind of sounds like you are boiling the fluid. I think a change of fluid, upgrade to a higher grade fluid, and consider heat sleeving the clutch line that runs by the drivers side exhaust manifold (or upgrade to a pre-sleeved stainless line).

That's not CSC failure, not to say it isn't on its way out, but no failure yet. When mine went my clutch pedal would literally stick to the floor board and I'd have to pop it back up with my foot.

Have you seen any black particulates floating in your clutch fluid reservoir?

What type of fluid would you recommend?

Okay well that's good to hear. Seems like all of us Z owners have to change our CSC at some point based on what I've read. Seems like Nissan needs to come out with a recall on it from all the issues... and I don't see any of that in the reservoir but the fluid has a blackish/brownish look to it

That black/brown fluid is telling you that you are way past your fluid change interval. You need to do a gravity bleed and get all that nasty out of the CMC reservoir. Recommended fluid would be Motul RBF600. You can change it out with Castrol DOT 3/4 brake fluid if you are in a pinch.

I just got it done like 4000 miles ago. I didn't think it'd need some again that soon. Or I wonder if they just used a crappy brake fluid

If the fluid is discolored, I would certainly recommend bleeding the system and replacing the spent fluid with a high quality DOT 4 brake fluid such as Motul RBF600 or equivalent. The loss of pressure could signal that you were boiling the fluid. It could also suggest that your CMC is on its way out. As indicated above, if the CSC fails, the clutch pedal will normally stick to the floor and there will be signs of fluid loss (... either fluid visible under the transmission bell housing and/or a drop in fluid level in the clutch fluid reservoir). If the CMC fails, the clutch pedal will often feel "soft", but sometimes will recover by pumping it a few times. For further advice, you may want to contact Joe at Z Speed Performance and/or Ryan at RJM Performance. They both have a lot of experience with the problems associated with the stock clutch system.

Yeah I'm gonna make an appointment tomorrow to bleed the system and replace clutch fluid. How many bottles of motul 600 will I need? Can I buy this stuff locally? I called around and not many people carry it. I will probably need to change my CSC and CMC sometime. But I'll just keep that in my future plans.

Also will I be fine driving it with dirty fluid for now... I could probably get all this replaced Tuesday or Thursday this week

The Motul RBF600 comes in a 500 mL container. One container should be sufficient ... but you may want to buy two just to be sure. You can always keep any extra for future use ... especially if the container has not been opened. (The fluid is very hydroscopic and will attract water as soon as the container is opened. The boiling point of the fluid will drop as the water content increases). You should be OK driving it with the dirty fluid for a few more days. Whatever's happened, has happened. I doubt things will change over the course of the next couple of days. Is there any evidence of fluid loss ... or is the fluid just dirty? You may want to snap a picture and send it to Joe at Z Speed and ask for his opinion.

The fluid basically just appears dirty. The fluid level seems fine. It's between the min and full mark. I will prob hit him up and see what's going on

Most likely crappy fluid. If it has ever been neglected, it will take 3 to 4 fluid exchanges to get cleaned up. I change mine ever other oil change.

i bought 3 500ml bottles of motul 600 to be safe. That should be enough for a bleed and replacement right?

Probably enough to do it 5-10 times. =)

Once you have the fluid changed, go ahead and put an insulation cover over the flexible hose that runs by the exhaust to the transmission. It gets really hot there. Joe at ZSpeed can help you or a local speed shop. The clutch hose is very close to the drivers side CAT and it will be very hot if you drive the car hard.

I use Motul 5.1 fluid and it works great.

I'll look under my car and see if I can find it.

I got the Motul 600 in today. Taking car in tomorrow to get clutch bled and fluid replaced. I'm sure it'll make a big diffference on how the clutch feels especially when getting on it. I've been gentle lately and clutch is working perfect but the dirty clutch fluid wasn't able to handle the aggressive shifting :/ lol not gonna let it get that dirty ever again!

Make sure they wipe out the reservoir with a clean lint free cloth. Need to get that nasty out of there.

Okay will do

Got clutch fluid bled and replaced today. My clutch feels great under normal driving conditions. I did some hard accelerations and right away clutch lost pressure. So I think I'm due for a CMC and/or a CSC replacement?

Hmm that is troubling... In the common case with our cars, CMC or CSC failures don't seem to accompany hard driving. Do you have any exhaust mods that would put more heat on the clutch line that runs to the bell housing?

I'd recommend contacting Ryan@RJM.. he is the expert at diagnosing this stuff and is super helpful.

If you are replacing the CSC then you'll need to replace the CMC also. The CMC is basically a one time use item and needs replacing when it has the fluid drained out of it. I'd recommend aftermarket for both.

https://www.z1motorsports.com/clutch...er-p-7397.html And https://www.z1motorsports.com/z1-pro...it-p-7340.html I found these on Z1. Would you guys recommend these products?

Parts didn't cost as much as I thought. Anyone know about how much labor might run

My exhaust is stock. And what's RJM?

The master listed here is the OEM one. Ryan@RJM sells an aftermarket one. I farmed out my clutch job and my mechanic told me he went with an OE-Equivalent master because the failure rates were much better compared to the Nissan part.

I don't have any experience with that cylinder delete kit... For slave I use the ZSpeed HDCSC and it has performed flawlessly for me. It's also less expensive.

$50-$100 (.5-1hr) for the Master. About $400 (~4hr) for the slave because they have to drop the tranny to change it. If your clutch needs replacement or you have been wanting an aftermarket clutch/flywheel it would be a good time to do it when replacing the slave. It would also be a good time to change to a stainless steel clutch line with heat sleeve... It's cheap so you may as well do what you can to keep the heat from the cats off of the clutch fluid.

RJM is a vendor here who makes adjustable clutch pedal assemblies and master cylinders for our cars. He is one of the really good vendors on here. It's a one man show and the guy's name is Ryan. link: RJM Performance

Not to be confused with RJM the company that is supposedly developing a new supercharger kit for our cars.. whose owner has a pretty sketchy past.

CSC or CMC problem?
 

The CMC is the same as the one in your car so it'll definitely work but is not an aftermarket replacement. The elimination kit will replaces the CSC. I've heard great things about it but there is a little maintenance required to adjust it from time to time. If you aren't comfortable doing that you might want to consider the Zspeed HD CSC. I'm running it in my car and it's worked perfectly.

As for labor, it'll basically be the same as a clutch install since you have to drop the transmission and an additional hour to an hour and half for the CMC replacement. Depending on labor rates where you live I would guess anywhere from $800-1,200.

Sounds like for now your Clutch Master Cylinder is dying.
Not too bad to replace, Flush the fluid well while you're doing it.

Nissan OEM Clutch Master Cylinder 370Z G37

When and if your Slave (CSC) dies this will keep the fluid much cleaner and less maintenance in the long run.
ZSpeed Performance Nissan 300ZX 350Z 370Z Infiniti G35 G37 Q50 Q60

Listen to Joe, the man knows what he's talking about.

I'm looking into getting this CSC. I would like to get the one you recommended but I'm on a tight budget ATM -_- I also seen it recommend a clutch pilot bushing when replacing the CSC. So how many of those pilot bushings would I need? And will the OEM master cylinder work fine or do you guys have any aftermarket ones?

Best thing to do is call him... He will get you set up in a matter of minutes.

Just one pilot bushing is all that's in there, It is in the back of the crankshaft and holds the input shaft centered. Oem master will work fine with this kit.

So In the near future I want to order my parts from ZSPEED. I take it you work for ZSPEED? Well I'm not sure if you could help me out or not on this aspect but I called a local transmission shop that does great work and they were acting iffy about me bringing in my own parts. They said they only will sell their parts to me and labor themselves. They said they only do LUK and OEM parts. This is b/c they have their own warranty and they don't like people bringing in pets b/c they have failed before. I told them these pets are better then OEM and it's solid products, they said they might consider doing it. Idk if one of you guys at ZSPEED could talk to them?

That'd be easier

Called another shop and they don't care if I bring my own parts in. They said labor would be $600 does that sound about right or too high?

That both CSC and CMC?

Yes

That's a pretty good price