New Clutch Install. Pedal won't return.

Mitco39

I dont think that would cause your issues, I mean if you had that leaking it would spray out of there when you pressed the clutch and pressurized the system. Not to mention a leak there would not pull air back into the system so much as let all the fluid run out. The way the upgraded CSC (which I am assuming you have?) is setup is to facilitate gravity bleeding and even after letting it gravity bleed you should have a stiff pedal right off the bat.

The fact that the pedal wont return leads me to think that even at the start of the stroke you have negative pressure in the line. Its this negative pressure that is going to hold that plunger to the floor. If you had a leak you would infact see the opposite. You would have no feeling in the pedal at all and it would feel like it was not doing anything.

The CMC has to be able to in effect breath into the reservoir so that at the start of every stroke your clutch system is effectively sitting at atmospheric pressure. If its not it will stick.

Question for you, where you able to gravity bleed the system? (IE. crack the bleeder and run the fluid through the system on its own) Mine would not gravity bleed which pointed directly to an obstruction in the CMC. I actually ended up pulling my CMC apart and taking a dremel to it to get it to work for the time being.

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2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
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m3chhawk

Nissan is doing all of this (which I am definitely beginning to regret). That being said when I asked him this morning if he followed the ZSpeed instructions, he said he let it gravity bleed for 15 minutes. But he never said if that was successful either.

When I went back by after work (the convenience factor here is that the dealership is literally on the way home and 3 miles from both work and home), the tech had left for the day. They said they were having a tough time finding the correct pitch bleeder screw (after I told them they were 3/8-24). I'm sure I had a "well derp" look on my face when I said I will go get them and bring them in the morning.

Anyway, here is a pic of the female end of the compression fitting on the bleed screw: http://i.imgur.com/pO1Zje0.jpg
You can see how it isn't concentric, although it should very much seal.

I'll take the new bleeder screws in tomorrow morning and if that doesn't get it (it won't), I'm bringing the car home so that I can do this myself.

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m3chhawk

Also, I'm beginning to think the small pool of fluid and droplets are just residue of what is left inside the bleeder screw. I'm going to make him blow it out with an air gun and then try it again tomorrow.

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m3chhawk

Also, out of curiosity, what exactly causes the CMC failure??

Sent from my Galaxy Nexus using Tapatalk 2

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m3chhawk

So replaced the bleeder valve. Still does it as expected. Here is the word from Nissan...

After bleeding, it feels/drives normal. As you drive for a bit longer, the pedal eventually starts sticking to the floor again.

Thoughts????????

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Baer383

If it feels good and then bleeds down then it is either the CMC or it still has air in it.

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2013 ZL1

754 rwhp 747 rwtq

m3chhawk

I think I'm going to bring the car home, drain all the fluid, and start over. Then if it still does it, go the CMC route.

There is just a part of me that feels like the tech isn't fully bleeding it....

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Baer383

Don't take the fluid out, alott of people keep bleeding and bleeding and get half azz results ,I had the same problem as you and Joe told me to tighten the bleeder then crack the line at the CMC let it flow for a few seconds then tighten it up I did that and my pedal was rock hard at the top and for the last 350 miles everything is still good.

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2013 ZL1

754 rwhp 747 rwtq

ChrisSlicks

My guess, they probably f'd up the threads by trying to use the wrong bleeder or they accidentally loosened the line fitting (just barely) on the CSC during installation.

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m3chhawk

Lunch hour update:

I have a co-worker that used to sling parts for Nissan and we have called around. There is a service bulletin for this exact problem:

2011 Nissan 370z Power Train Service Bulletin 353407
NHTSA: Action Number: 10051926 Service Bulletin Number: 353407
Report Date:Apr 10, 2013 Component:Power Train
Summary: Nissan: clutch pedal does not return to rest position.

The remedy is GTR brake fluid. I talked to Joe (who I would like to say has been a rockstar and answered every one of my retarded questions) and he said this usually doesn't fix it.

Nissan is going to re-bleed (following Joe's bleed instructions perfectly) using GTR fluid at their cost. If this doesn't fix it, they are over-nighting a CMC and replacing under warranty. If this doesn't fix it, they are under strict orders to take it out back and light it on fire.

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Mitco39

I still put all my money on a faulty CMC. Mine didnt make sense either, but it is what it is

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html

m3chhawk

Me too. I think the thought behind the GTR fluid is that is covers up that slop in the CMC.

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ChrisSlicks

No, the high-temp fluid is to prevent the fluid from boiling. The cheap DOT-3 fluid they put into the clutch system is easily boiled especially given how close the clutch line runs to the exhaust (there is a small piece of insulation) and the heat from the clutch etc.

The #1 reason for the sunken clutch is boiled fluid, creating air pockets.

The #2 reason is failed CSC (leaking fluids, empty reservoir).

The #3 reason is failed Master.

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Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

GaleForce

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m3chhawk

New CMC and GTR Dot 4 on Thursday and everything was fine again. Got ballsy and took it on a 900 mile round trip this weekend and everything held just fine. Thanks for all the help guys. It appears there is no mileage limit to the CMC failure. They appear to be a one and done most of the time.

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