CSC Failure Symptoms?
 

I just got my car back from the dealership because my Steering Lock Unit failed and had to get it replaced and as I was driving it home from the dealership, it felt like my clutch isn't as firm as it was before....:mad:

I am really hoping this is not a CSC failure. I haven't been checking my clutch fluid level but I just checked it and it is 40% full in-between the min and max lines.

The clutch does not "stick" or drop to the floor as many others have experienced with a failing CSC but the clutch feels softer.

When should I begin to worry about this being a CSC failure? Anyways to prolong the failure? Top off the clutch fluid reservoir? Any tips or advice would be greatly appreciated. I think I am going to leave it parked and not drive it for now.

And around how much does it typically cost to get replaced by the dealership? I have read through the CSC failure threads but have seen people post costs anywhere from $400 to $1800 (parts and labor).

Thanks

The first and cheapest thing to try would be to replace the clutch fluid with something like a Motul 600 or one with a higher temperature rating than the OEM stuff.

If the fluid looks dark, then you definitely need to replace it. If this works, you'll get a lot more life out of the CSC. Mines only gone to the floor once while at the track, and never did it again.

You don't mention what year yours is or how many miles you have.

I don't think our manual recommends it, but I always flush/change my Clutch and Brake fluid every 2 years. It was part of normal maintenance schedule on my BMW and I never had any problems. The BMW mechanics were pretty insistent about it.

They probably drove your car hard and boiled your clutch fluid. Did you check the mileage when you dropped it off and picked it up? I always make sure the dealer is aware they are not permitted to drive the car without my explicit authorization and even then only for diagnosis purposes.

Change the fluid is first option. Change master cylinder is second option. If neither of those fixes the pedal, then you're likely looking at a new CSC. The problem is the dealer wants to charge your $1000+ to put another shitty OEM CSC in there. Get one of the ZSpeed options (HD CSC or CMAK) and have a competent mechanic do the install. Expect 7-8 hours of labor with labor costs running $80-120/hr depending on your region.

Thanks for the responses guys. No I did not check the mileage since the odometer backlight would not turn on due to the Steering Lock Unit issue.

Unfortunately, I think the dealer may have driven my car but it would be hard to blame them for my clutch "feeling" softer without sufficient evidence.

Does anyone know the part numbers for the OEM CMC and CSC? In the event that I need to tow the car to the dealership/independent repair shop, I would probably buy the CMC and/or the CSC online for cheaper instead of paying the marked up dealership prices.

So either way, if I chose OEM parts or aftermarket, I would be looking at $1000-1500 for parts and labor? I JUST paid over $1000 for the stupid Steering Lock Unit.

At what point would the clutch start sticking and my car would be undriveable? Would changing and topping off the clutch fluid prevent that?

Under no circumstances should you put an OEM slave back in that car.

First thing you need to do is pull the fuse on the steering lock (link in my sig to more info) to greatly reduce the possibility of failure in the future.

Then change clutch fluid as mentioned by others above. Also see JARblue's comment above.

Like the others have said, first step would be to bleed the clutch system, and re-fill the reservoir to the max line with a high quality DOT 4 brake fluid with a high boiling point such as Motul RBF 600 ... then regularly check the fluid level in the reservoir. If you notice a loss of fluid, you would then be looking at replacing the CMC and/or CSC. Judging from your symptoms (i.e., soft pedal feel, without the pedal going to the floor), I suspect your CMC may be the issue. If the CSC fails, it's usually catastrophic (i.e., complete loss of pedal pressure). If you do need to replace the CMC and/or CSC, look for after-market solutions. As Chuck says, do not simply install another OEM CSC. Check with Joe at Z Speed Performance. He carries a heavy-duty CSC as well as a clutch movement alteration kit (CMAK) that re-locates the slave cylinder outside the transmission bell housing. Both are high quality parts. In terms of a replacement CMC, you may want to check with Ryan at RJM Performance. He carries a Gen 2 HD CMC. That said, changing out the clutch fluid may solve your problem ... at least in the short term. Recognize that failure of the stock CMC and/or CSC is not uncommon ... some view them as ticking time bombs. Also, in terms of your steering lock failure, what model year is your Z? IIRC there was a recall issued by Nissan covering the cost of replacing the unit for certain model years ... however, I'm not sure of the details. Someone else can likely fill in the details for you. Trust this helps!

Wow thank you so much for the insightful and prompt replies. I greatly appreciate it. I will head to walmart and get some motul 600 and top it off and see what happens.

No, don't just top it off. Bleed it. It'll get you down the road for a while. But be aware that there mill more than likely come a day when you come out to your clutch pedal on the floor. Be ready.

What is the concept behind completely bleeding it to solve the issue? I would assume that the fluid currently in the system has a lower viscosity and has been degraded since its been temperature cycled and that if it is replaced with brand new, higher viscosity, fluid that the fluid pressure will be higher resulting in higher clutch pressure? And also the higher viscosity fluid will help mitigate leakage? Would it be save to assume that if the fluid is topped off that the clutch will not sink to the floor?

Get all of the old waterlogged fluid out and replace with fresh fluid with a higher boiling point. Just topping it off will do nothing.

And further more the "ranger" method that is floating around the interwebz is BS and won't do anything for you. As the fluid doesn't circulate the only way to get rid of the bad fluid is to flush/bleed the system. It's completely possible to have pristine condition fluid in the reservoir and completely black fluid at the slave cylinder.

You need to pull the steering lock fuse before it happens again. Even the replacement you got will still fail eventually. You need to pull the fuse before it breaks again, because once it fails again pulling the fuse wont do anything. Pulling the fuse only works with a working unit so you would then have to pay for another replacement and THEN pull the fuse. It takes 5 minutes, and you wont even get your office clothes dirty. See the DIY in southark's signature.

The soft clutch is probably from boiled fluid. You should bleed and replace the fluid with high temp stuff like motul rbf600 or if you just want to pick something up at autozone valvoline synthetic dot3/dot4 isnt bad. Good fluid also wouldn't hurt in regards to the life of your csc.

The csc's in these cars are garbage. It WILL fail eventually. It may fail at 100 miles on the car, or at 100k miles, but it is a matter of when, not if. The CSC is around the input shaft of the transmission on these cars, so when it fails it requires dropping the transmission which is labor intensive ($$$). My best advice to you is keep some extra money around for when it fails if you do not want to go ahead and address the issue now before you get left stranded somewhere.

When it does fail, you should under no circumstance put an OEM replacement in the car. At the very least you should replace it with Zspeeds HD (heavy duty) slave. But there are 2 other options I highly recommend. The first is the Zspeed CMAK kit. This kit comes with the Zspeed HD slave, but it moves the slave outside the transmission bell housing and uses a fork that reaches into the bell housing to actuate the clutch, similar to late model fords. aka, this means that if the slave ever fails again, you can replace it without having to drop the transmission. Z1 motorsports also makes a csc elimination kit, which is similar in function to the cmak kit, but it requires minor adjustments over time as the clutch wears. The cmak is set it and forget it.

Zspeed CMAK kit : ZSpeed Performance Nissan 300ZX 350Z 370Z Infiniti G35 G37 Q50 Q60

Z1 csc elim kit: https://www.z1motorsports.com/z1-pro...it-p-7340.html

Zspeed HD slave on its own if you don't get one of the above kits: ZSpeed Performance Replacment HD Clutch CSC Heavy Duty Slave Cylinder Kit

If you look in the vendor classifieds section of this forum you may be able to get a little discount, but I'm not sure.

Also here is a sticky on steering lock failures: http://www.the370z.com/nissan-370z-g...se-sticky.html

And a sticky on CSC failures: http://www.the370z.com/engine-drivet...-failures.html

Your whole system - CMC, lines, CSC - has bad fluid in it and it needs to be completely flushed/replaced. Just topping off the CMC will be, at best, a temporary band-aid.

In addition to being less effective as a hydraulic fluid, your fluid contains "dirt" that will erode seals in the CMC and CSC.