I've noticed that my clutch gets soft when I find myself in heavy gridlock for an extended period of time. The more I have to be on and off the clutch, the softer it seems to get. A few times the clutch pedal has gotten stuck mid release after being in heavy traffic. I've had to put my foot underneath the pedal and raise my foot to get it back to its normal position.

I'm not riding the clutch. I usually give it a bit of gas, pop it back into neutral, and coast when in heavy traffic. '07 base. 50k miles. Everything related to the transmission is stock. I'm pretty sure the previous owner hasn't replaced the original clutch.

Is this a known issue with Zs? If not, what might be causing this?

 

I would start by checking the clutch fluid. If dirty / never changed, then :

https://my350z.com/forum/maintenance...intenance.html

 

It's most likely your Clutch Slave Cylinder(CSC).

Here's some threads regarding that issue.

https://my350z.com/forum/engine-and-...-w-pics-2.html

https://my350z.com/forum/engine-and-...h-problem.html

https://my350z.com/forum/engine-and-...the-floor.html

https://my350z.com/forum/engine-and-...the-floor.html

 

I had a similar problem, i think it was the clutch fluid overheating. I put in some higher temp fluid in there and I havent had a problem since, you could try that first as its an inexpensive fix

 

Check to see if foil shield is covering the clutch fluid line from MC into trans. If it's removed or replaced with stainless line, then it's very likely the heat from cat is boiling the fluid. Or, as mentioned above, it could be the usual slave cylinder problem made worse by the heat of being stopped in traffic.

 

Awesome. Thanks for the info and links!

 

I had a similar problem. Took it to the dealer. They replaced the clutch, flywheel, csc. Couldn't fix the problem till they realized the 2day foot hose carrying the fluid was pinched. Got it all fixed under warranty.

 

Not 2 day. Meant 2 foot*

 

old clutch fluid and probably needs to be bled.

 

Everything the others said is accurate. Add that you can get a stainless line installed, add some heat wrap and run a Motul fluid. I used to have this happen with my TN kit, had to pull the pedal off the floor with my foot.

 

Same used to happen to me. Had the dealer change the slave cylinder, still occurred. Then the dealer installed a heat shield down there, I forgot the exact name of it, but I believe it's a Nismo piece, and it solved the problem. That shield should really be a stock item.

 

i changed out slave and master when i had that problem and it ended up that i didn't have it properly bled. These systems have a weird loop in them that traps bubbles. It took me a solid 2 hours of bleeding to finally get it working correctly. It's by far not an easy bleed.

i recommend doing it how i did it the second time: get a small oil can that is an oil pump. Fill with brake fluid and attach it to the slave cylinder bleed port. Force fluid backwards through the system with it up into the master cylinder. Air bubbles like to travel upwards so you are pushing them the direction they want to travel. Worked perfectly for me.

 

Sounds like heatsoak is the most likely culprit. The heat shield + new fluid should get it sorted out. I'd recommend a fluid with a higher boiling point, as well. What're you running now? We stock Motul RBF600, as well as some others. The down side to running a fluid w/ a higher boiling point is that you need to flush and refill more often because they're more susceptible to moisture contamination. ATE Super Blue has a good boiling point and claims to be good for 3 yrs. I'd personally bleed it every year, though.

 

Very interesting. Couple of points related to my situation though. Only occurred on hot days when idling in stop-go traffic. The car had less than 30k on her at the time. Never tracked. The dealer replaced the slave cylinder for me (warranty), so I don't know their bleed procedure. The heat shield seemed to cure the problem, although I didn't have the car for much longer after that.

I think in general, the car has a heat issue with the clutch fluid. Whether that manifests as an early slave cylinder replacement (which it seems like we've all had to do), or air bubbles caused by boiling that need bleeding, heat seems to be the culprit. I was quite annoyed actually once I heard about the heat shield fix, because this had been a problem that lasted for 2 years off an on for my car.

 

Trust me here as someone that has completely disassembled the engine bay. The heat sheild and fluid change will go a long way, add in the SS line and you are almost sure to solve the issue. After doing the above I never had a problem again... the carbon on carbon clutch in traffic is a different story.

 

I'm guessing this is the heat shield?

http://www.courtesyparts.com/11235a-...8-p-15367.html