Sticky: (Official) 370Z Clutch Pressure (CSC) Failures

Bananaz

Just replaced mine with the z speed csc. The oem one was beyond soaked

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radensb

I just had my MSC and CSC replaced back in February of this year. I went out to go to work one morning and the clutch peddle was on the floor. I could drive the car, but barely. Had about an inch or so of engaugment. I called my dealership to arrange to get it down there during my lunch. When I went to take it there, I had no peddle at all. Had to get it towed. They eventually replaced my MSC and CSC, which they said was shot. It worked great.

Then last night going home from work, I notice the peddle is getting soft and mushy again and not engaging when it should. This morning driving to work, I almost didnt have enough peddle to change gears and had to pull the peddle up off the floor a few times. I pulled off the freeway and called the dealership, who said they would have to call me back ...

So i figured I would try to limp it to work as I was pretty close. At least I could wait for their callback in my office. At this point, it had been 10 minutes since I pulled off the freeway. When I tried to drive back to work, the clutch worked fine!? ... for about 5 minutes, then started to lose pressure again.

I tested it out at lunch today. It seems it act up when I drive for a bit (after 10 min or so) and more so at freeway speeds when I don't shift for a while. If im in city traffic, and pump it for a bit, it returns to normal for a little while. I have full fluid. Im not rough on the car at all. I thought I had this taken care of about 6 months ago!

Bananaz

You need to replace it with the z speed csc and you're set!

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radensb

So the dealership never got back to me... of course. So I tried to limp the car home after work. The clutch engagement got so bad that I had to pull off the road as I was having trouble shifting gears. The odd thing was that the clutch came back to normal after having the car off for only about 10 seconds! So I started driving home, but it only took about 60 seconds for the problem to return, but at least I could get her home.

HMMMMM.....

All I did was stop the engine, so I concluded that my issue had to be heat related. ie: boiling fluid. Now back when I got my MCS and CSC replaced, they noted that they put in the Nissan GT-R hydraulic fluid which is supposed to be rated to take the heat.

I really didnt want to deal with the hassle and the dealership (or the cost), so I decided to just bleed the clutch myself. I used MotorMedic DOT 5 fluid from GUNK:
Amazon.com: Motor Medic by Gunk M4011/12 DOT 5 Brake Fluid - 11 oz.: Automotive
UPDATE TO UPDATE:
DO NOT USE U.S. DOT 5!!! UUUGGGHHHH.... Apparently the site I was reading has a DIFFERENT spec for "DOT 5". DOT 5 is NOT COMPATIBLE with DOT 4 and below... Even though I didnt mix the DOT 5 and old fluid, DOT 5 is not good for the seals. So I am going to immediately flush out the DOT 5 with DOT 4 when I get home from work.

It was the only thing O'Reilly Auto Parts had that was rated for 356°F (wet boil) and 500°F (dry boil). When I bleed the old fluid out, it was full of bubbles and black. Definitely didn't look good. WTH?? After 6 months of typical commute driving (~15 miles each way)?

Being that the MotorMedic was DOT 5 and can't be mixed with DOT 4 and below, I used the entire 11 oz bottle to flush out the old fluid until the new (purple) fluid came out clear any without bubbles.

Result:
Clutch felt great, so I took her for a spin around the block. No issues. This morning during the commute to work, I had zero problems. We'll see if anything acts up in the next few weeks.

fuct

yea i think it says in the manual not to use dot 5. :/

1slow370

dot 5.1 is compatible dot5 is silicone fluid and is not.

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radensb

Yeah, I think the site I was referencing was using the European standard. What they call DOT 5 is equivalent to what we call DOT 5.1. And this is the only type of fluid that is not compatible. Just my luck. Go figure...

So yeah, performing another flush tonight!

Indiana102

Just a heads up, but all parts put in by Nissan all have a 1 year warranty. So, since you just had this done 6 months ago, they will still be liable. Stick it to the man!

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radensb

Actually, Nissan didn't put it in. I got the car used from a FORD dealer and have to go through them. Granted, they give it to a Nissan dealer if they needed to. It probably wouldn't cost me anything to have them fix it again... but I didn't want the hassle.

But then again, look where it got me.... with the wrong fluid... lol

radensb

Ok, so I got a liter of ATE Typ 200 and used about half of it to flush out all the DOT 5 fluid from the clutch hydraulics. What a PITA! Since the DOT5 silicone is less dense than the DOT4, the DOT 5 would sit on top of the DOT 4, thus all the DOT4 was bleeding out before the DOT 5... I had to vacuum out all the fluid until the clutch system was empty. I put in some DOT 4 and vacuumed it out until there was no trace of DOT 5 left in the catch can. Used about 1/2 a liter to do the flush, then filled the system with DOT 4 using the typical bleeding process.

Clutch feels great! I read many people saying that the silicon DOT 5 is bad for seals and when it is mixed with DOT 4 is create a goo, or sludge. I do not think this is true. The silicone is inert and should have zero effect on seals. Also, I mixed the DOT 5 and DOT 4 together in the catch can. They didn't not interact at all. It was like oil and water. Even over several days.

MJB

IDK, I just think you guys over think/analyze when it comes to fluids for this car. There is nothing special DOT 4 or 5 has over DOT 3 other than they have a higher boil point. Unless you are on the track, you are not going to boil your clutch fluid with street driving. The problem with the stock slave cylinders lies within the seal itself. Its a crap design and it fails, regardless of what fluid you put in there. I read thread after thread of people spending hundreds of dollars on high end oils, expensive brake fluids, ect, when in reality its a waste unless you are building a flat out race car. DOT 3 is perfectly fine for our clutch hydraulics system. When dealership mechanics starting put in this so called "GT-R" fluid (which is just DOT 4, nothing special about it) people now think its a cure-all for these CSC/CMC issues, SMH.

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09 Nismo #0483 sold. Viper or C7 next time around.

radensb

Have to disagree with you here. My fluid did fail within 6 months of normal driving and zero track time. And according to my service record, it was GT-R fluid. When I flushed it out, it was black.

MJB

The clutch line has a thermal fiberglass wrap on it, so unless that was removed and the line was actually touching the cat, how is it going to boil under normal street driving? And about your fluid being black, that's because the seal on your Csc was going bad and allowing dirt and debri into the system. If you feel the Dot 5 is a fix, then have at it... But I guarantee you that your stock Csc will fail again.

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09 Nismo #0483 sold. Viper or C7 next time around.

Bananaz

Everyone just needs the Z speed HD CSC..if you keep replacing your failed OEM CSC with another OEM CSC..then shame on you!

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radensb

The fiberglass insulation is a joke. It only insulates the rubber hose that jumps to the CSC. The metal tube that runs up to the MCS is completely un-shielded. Im sure that the stock CSC will go out again, but seals failing after 6 months? I dunno about that. I had no leaks and I am not rough on it. It has to be heat related. How else can you explain regaining a normal feeling clutch after turning the car off for 10 seconds? Then it deteriorating to the point of 'un-shiftable' after another 60 seconds of driving?

I will ask about this when my CSC goes out again. I'm have a 5 year extended warranty that covers this type of failure. I thinking that they will not want to put anything other than stock in or it would void that warranty, blah blah blah... Nevermind that its higher quality and will prevent them having to fix it again in the future.... Warranty Logic.