Sounds like your clutch master cylinder may be problematic. That's where the junk in the reservoir came from.

 

I have been having the exact same issue with my 2008 G37s. Started my car up last night and clutch would engage very low to the floor and have barely any pressure after engaging.

This morning i looked at the clutch fluid and it seemed very dirty so i went along and tried to flush it out. The fluid would not flush at all, i ended up taking a syringe to it and finally noticed clean clutch fluid flowing through, but there was still a lot of air bubbles. I kept trying but it didnt seem to get any better (i could not get rid of the air bubbles).

I pretty much gave up and just let my car idle for 15 min. At first the pedal was stuck to the floor with no pressure, came back 10 min later and the original symptoms were back (engaged very close to the floor with little pressure afterwards) 5 minutes later the pressure in the pedal seemed to go back to normal and the car drove fine.

Was there a solution for this? I feel like I have a bunch of air in the line that i couldn't get rid of although the clutch feels fine right now.

 

Bleeding the clutch in our car takes patience. Suck out the dirty fluid from the reservoir and wipe out as much of the contamination as possible. Refill with clean fluid. Only pump it about 10 times SLOWLY. Pumping it fast induces air into the system that's hard to remove. Bleed it slowly and close the bleeder before you've released all of the pressure. Repeat as many times as necessary. It takes a while. If it's particularly contaminated you may need to suck out dirty fluid from the reservoir and refill with clean fluid a time or two during the process. Keep going until the fluid is completely clean. And to get the system pressurized, only crack the bleeder open a little bit (not all the way) and only enough to bleed any air out but not bleed off all the pressure as I mentioned before. It takes more effort then bleeding brakes.

 

I was on my back under my car for about 4 hours trying to flush the fluid. Clearing the reservoir about 6x and I could never get a steady stream of fluid to flow out of the bleeder. There seemed to be a lot of air bubbles still when I decided to call it quits. My clutch seemed to go back to normal after it was limp for 10 min and I've been driving it the past couple of days with no problems. Im not sure if i should take it to the dealer and get them to flush it for me or If i just continue driving in hopes of everything being fine.

 

From reading a number of threads on here and the 370z site, if you're having issues bleeding, it could the master cylinder is worn. You can try disconnecting the clevis fork from the pedal to fully compress the piston into the MC. This would ensure there is no air in the MC and is the equivalent of bench bleeding it.

If you're still unable to get a hard pedal, then it's time for a new MC. Given the age of the car (2008) and mileage, it's likely time for a new MC anyways.

As BB pointed out, it's important to pump slowly. Same for when the pedal is lifted off the floor; lift slowly.

 

Mine did exactly the same thing starting at around 55K miles. Bleeding did not make a notable improvement, even had the dealership bleed the system and still no improvement. I finally installed the RJM Performance clutch pedal assembly and the problem is gone. Clutch action is much more linear and uniform. Still don't like the G37s clutch, especially compaired to the clutch on my 12 Corvette Grand Sport, but it's miles better with the RJM assembly than it was! It's a pain in the neck to install, but it's worth it! Runs around $275 for the kit.

 

My thought exactly; are they blind or just stupid..?

 

Just to add to this thread, I had the same problem. Trying to bleed the fluid, it was very frustrating even though I was using every unassisted technique in the book. Tried for hours, it would only drip out, still have air, etc.


Rented a vacuum bleeder from Autozone for free, finished in honestly less than a minute, perfect bleed, no air, perfect pedal after. Just operated the vacuum bleeder and had a helper monitor the fluid level up top and top off accordingly(didn't need much).

Also, for those who don't know, a vacuum bleeder is different than a power bleeder. You attach it to the outlet where the fluid comes out, build vacuum and it will suck the fluid through. It's very easy.

 

The issue I've had in attempting to vacuum bleed the clutch is the tiny bleeder. It's too small for me to get a wrench on it to turn and also get a hose on securely on the nipple that doesn't fall off. What did you do differently?

 

I have recently came across a major issue. My 5th and 6th gear suddenly stopped engaging. Before this issue I already could not put it in 5th gear without it sounding like grinding and it would kick the shifter into neutral, from time to time if I put it in with extreme sensitivity it would actually grab on to 5th but just a few times.. I mean the clutch pedal feels pretty normal, I could be wrong. Now my shifter goes into 5 and 6 and stays in gear however I gas it and it revs up as if it was in neutral. I bled the clutch fluid just about 2 years ago. It's a 2011 g37s with 59k miles(got it when it had 26k miles) I figured it's time for a clutch replacement. Maybe even a gear box rebuild since I flushed the gear box fluid and it had tiny metal particles.
What threw me off was the fact that my 6th gear is now not engaging. My clutch fluid is slightly under max level now and somewhat dirty. I will proceed to leakage inspections by the cmc and the csc. Thereafter do a clutch fluid bleeding and recheck engagement on 5th gear(which I know is out), and engagement on 6th gear. Regardless of the clutch fluid service and inspection, shouldn't my 6th gear engage (clutchless) at the right speed and rpms???? Is my transmission already giving out?? Or the clutch slipping?? It don't smell like rotten egg.Or can I buy some time by replacing the master clutch cylinder?

 

Sounds like trashed synchros in your transmission perhaps.