I did a DE event today at a local road course and had intermittent clutch problems. My car is an 07 Enthusiast that I bought used with about 60k miles on it. At the end of two different 25 minute track sessions the clutch pedal got mushy and would not return all the way. It never stayed all the way down and I was able to shift. Within 10-15 minutes of coming off track it would be back to normal.

I have never changed the clutch fluid but the level was fine. No leaks around the master cylinder. Could not get under the car to look at slave cylinder but no obvious leaks. No problems on 45 mile drive home.

Is this just an issue of the (probably old) fluid overheating/water in fluid? Will a higher grade fluid solve the problem? Are there other things that need to be done to prevent this?

Thanks for any help.

 

Change the fluid to Dot 4 , try it again. You should be good.

 

there was a recall on the csc on the 07 models. if you dont already know this.

 

csc?

 

I second this. I had the same clutch problems at my first event when I was completely stock (90F-100F+ weather!). Switched to a DOT4 like ATE Blue and no problems ever since.

I also had the CSC recall done before the first event so good chance it's only your fluid.

 

I'll definitely change the fluid. Still not sure what the 'CSC' is or how to tell if the car has had the recall done.

 

CSC = Clutch Slave Cylinder.

 

Here you go. https://my350z.com/forum/4986220-post1.html

 

Surprised that nobody has mentioned driving technique. OP-are you using heel-and-toe downshifting? Can you rev match accurately? If not, your clutch (and syncros) will really take a beating and build up heat/friction. Learning how to do this smoothly and unconciously will not only help smoothness and speed, it'll also help with your clutch problem.

 

I had the same problem once, and fresh fluid fixed it. It's good to buy nice stuff like motul rbf600 or ATE super blue, but I think it's more important that its fresh. I used a cheaper DOT3-4 fluid before a track day because i needed fresh fluid but couldn't find the good stuff and it worked fine. New cheap fluid > old expensive stuff.

 

Excellent point! I am learning to heel-toe. Practiced it more this time than previous track days. I rev match when I don't heel-toe. Most of the time I do it fairly well but I'm sure during each session there are plenty of times when it is not smooth or the drive train gets over rev'd. I'm definitely not to the point where I'm doing it unconsciously. That will take some time.

I can remember coming off the clutch pedal a number of times when the revs were not well matched but it was never enough that the car lurched hard or the rear felt like it was trying to lock up. So I don't think it was ever severe, probably just too often.

Hope I have not damaged the clutch itself.

 

I had this happen at Cal speedway on my 03 with an 06 drivetrain. Switched to a steel braided clutch line and changed fluid to motul. Never happened again.

 

I had this happen at the track too and changed my fluid, and just try to make sure I have fresh fluid in there, and I havent had the problem come back

 

thanks for this info.........................................

 

The fluid does have a lot to do with it but on the early 07's the clutch slave cylinder design is garbage. Any slave cylinder inside the transmission heats up and heats up the fluid to non useful levels which defeats the purpose of a slave cylinder or a clutch.

This is true with the 350z, Z06, etc. Check to see if it's under warranty and get it replaced, if not get the upgraded slave cylinder, SS line, and upgraded fluid. It'll never happen again.

 

The slave cylinder is inside the bell housing? Why? That's just nuts. Not only is there the heat issue, but doesn't that make it hard to work on? I mean slave cylinder problems are that uncommon and when they are easy to get to they are usually easy to fix.

I've got like 100 miles left on my warranty. I need to get it to the dealership and see if they will replace it, either under warranty or as part of the recall.

However, it clearly has not failed since it is working fine now.

I'm sure my problem was cheap/old fluid, poor downshifting plus the silly location of the slave cylinder. I can only change two of those.

jwttz, do you have a source for a braided stainless line?

Naut, thanks for the link.

 

The CSC is mounted on the outside of the bell housing. It is pretty easy to change out if it's not still under warranty. I had some issues similar to this, but my situation was way worse. Mine would drive after it cooled down, but I could smell burnt clutch the whole time. It was really bad. I pulled the tranny and half the disc had disintegrated and the other half was barely on there. I'm sure that is not your issue, but if you change out everything and put fresh fluid in then it may be. Biggest thing was that it smelled like burnt clutch all the time. Even at idle. Good luck!

 

The OP owns an 07, his car has a combined slave and throw out bearing. http://www.google.com/search?q=hydra...iw=768&bih=928 as you can see, they are internally mounted.

 

I didn't know they were different from the older models. My bad. Good call terrasmak.

That sucks then if the OP needs to replace that. You have to pull the tranny then right? I would imagine there isn't some kind of access panel or something to get to it on the bell housing?

 

I understand. Learning to heel-and-toe downshift takes time. Keep practicing even at low speed turns on the street. If you're not rev matching while performing a heel-and-toe downshift, you're really not doing it correctly. It's the entire reason for using that technique.