Mushy clutch

Dbaxter

Hey guys so this is a very serious question. I'm sure some of you have gone this the mushy clutch issue the Z has, mine is a 2009 and after CSC fix this is the only problem I have. I know it's because Floridas heat this summer but I have upgraded brake and clutch lines, fluids etc and not much has changed. Does anyone have a solution to this problem? It's bothering me to the point where driving the car is no longer fun and I'm strongly considering trading it in for another car like an Evox. Also has anyone experienced

this issue in the newer model Z's '14-'16? Any feedback is appreciated. PFA

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JARblue

It's your clutch master cylinder ... they may not have put a new one in when you got the CSC replaced. But even if they did, the seals are easily compromised by contaminants in the system leading to the mushy pedal symptom. I seem to be one of the more extreme cases, but I've replaced my master four times now in 80K miles

RJM Performance just came out with the first heavy duty aftermarket CMC for the Z. I just installed it last week. His clutch pedal assembly is awesome also.

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Dbaxter

First off, Thanks for the input. This issue has taken all the joy out of driving this car and it's caused me to no longer even want it so I'm hoping to end the nightmare. I replaced my master cylinder at the same time as the csc, but you're saying the master cylinder can still be bad. And I've heard nothing but good things about the RJM pedal and plan to purchase one, will it be a good idea to change master c again at that time Then I should be good? This issue occurs a lot more often during the day when it's hot and at night it's normally fine and doesn't loose pressure.

JARblue

Your master cylinder is already showing symptoms of failure. If you're going to get the RJM pedal, I highly recommend the HD CMC. Installing the new pedal without doing anything about your current master cylinder is likely not going to give you the pedal feel you're looking for. But replacing it with another OEM master that is prone to failure isn't something I would recommend.

The fact that the soft pedal happens more when it is hot makes sense because the fluid thins as it heats up. The thinner fluid gets by the master cylinder internal seals easier.

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Larso1

Before you do anything else, at least go thru the air bleed procedure to make double sure it isn't just trapped air in the line/master-slave cylinders. Heat expands air and will create a larger void in the system, causing a mushy feel. At night when it's cool, the air volume contracts, smaller void, more positive feel. Worth a shot

Dbaxter

Okay I've heard nothing but good from Rjm so ill go with that HD cmc and pedal at the same time. Id rather not have to go through more replacements of the master cylinder as yourself and than i already have. Ill post feedback after i get them and install.

Dbaxter

I've tried doing so a few times and its been the same issue just during the day and hard driving. i put rbf motul 600 fluid in and topped off as i bled.

SouthArk370Z

More than likely, JARblue is right about the MC leaking. Before changing, make sure the system has been flushed very well. Flush it until you think it's clean and then flush it some more. Otherwise, you will just suck the old "dirt" into the new MC and you're back where you started.

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Jsolo

This thread highlights the importance of periodic clutch flushing. The system holds very little fluid (prob 3-4 fl oz) and contaminates as it's used (clutch disc particles, seal particles, etc). By changing the fluid at least every 2 years you reduce the risk of these contaminants further damaging the system.

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Dbaxter

Will do, so before any installation of a new MC just make sure that the system has been flushed out to the point where theres no doubt its clean?! Thank you

SouthArk370Z

Yes. You have purged the lines of air (I'm assuming you did it correctly) and don't report any external leakage, so that pretty well narrows it down to internal leakage in the MC or CSC. IIRC, there's nothing in the CSC to bypass, but not sure. That leaves us with the MC. The most common cause of internal leaking is contaminated fluid. Brake/clutch fluid ain't cheap, but the volume is low, so go wild.

Depending on how much crud is in the system and just how anal you may be about such things, you may want to remove the lines and fittings and do a good bench cleaning before re-assembling - or replace them. Probably overkill.

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Larso1

It seems strange that a late model car should have so much trouble with such a simple thing as a clutch line with slave and master cylinders. I mean, they've been in existence since the early 1900's with good reliability, to the point I've personally never heard of an issue with them. My '97 Maxima has the original master and slave cylinders at 200k miles, only replaced the clutch. Maybe one master or slave on all of the manuals I've owned since the 1960's. Really weird...,

SouthArk370Z

My guess is that temperature plays a big part. Newer engines run a lot hotter than they did back in the 60s. With the undertray, the Z traps a lot of heat around the transmission which causes fluid to degrade faster. But, yeah, that's just a guess.

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Elmo370z

Back then they made parts that would stand the test of time, people acutally gave a shyte. NOwadays its how can we make it cheap as possible.

Dbaxter

So I know it's been a while, still no luck so I'm going to be getting the z1 csc elimination kit and replacing the master cylinder. I will be upgrading my clutch as well is it recommended that I get a stage 2 or stage 3 clutch? I'm looking into a south bend