I could use some advice on Master/Slave cylinder issues...
 

Please forgive me for not having done all the research that might be expected by forum veterans, but I am currently 1.5 months into a 3.5 month road trip around the lower 48, which is limiting my forum search/reading time.

2010 Roadster Sport/Touring 6 spd. Purchased with 28000 miles in Feb. Now at 38000+ miles.

A week or two back (can't be sure), I started noticing an occasional ca-thunk from my clutch return pedal when shifting quickly, like it sounds when your foot slips off the partially depressed clutch pedal.

On Monday that turned into the clutch pedal sticking about 4 inches from fully returned and I could flick it up with my toe. I checked my fluid level and it read full. This lead me to deduce that I likely had slave cylinder issues, even though the previous owner said he had replaced the clutch at 10 or 15k miles, leading me to surmise that he may have replaced the slave at that time.

I took the vehicle to a performance oriented auto mechanic in Savannah. He said he was overbooked, but agreed to have a quick look. He attempted to bleed the system which led him to discover that the lines or perhaps reservoir was filled with goo from deteriorated rubber parts.

At this point the pedal would no longer return at all. A discussion with Joe at Zspeed informed me that he is out of the parts needed to address the issue and relocate the slave. Upon hearing that the pedal was now not returning at all, Joe suggested I have this shop replace the Master cylinder with a new OEM one as this might get me moving again and buy me sometime to further trouble shoot and address the issue.

He said if the slave was not too bad, that this may get me moving again. On his advice, I had the CMC replaced and much to my surprise, the clutch now drives pretty much like it did before.

Is there a chance that my slave cylinder is OK and a new master is all I needed?

How do I determine if the slave is going out as well? If it is going out how much longer can I drive it before I will start having more trouble?

Is there a good 370z mechanic that is north of Charleston to which I might have Zspeed ship the parts and have further repairs executed.

Any advice is appreciated.

Thanks


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No, I do not. The previous owner said he installed a new "competition clutch" and "billet fly wheel" at around 10 or 15k miles because the stock clutch was "slipping." When I said clutch slippage at 15k seemed odd, he quipped, "I did not like the clutch, so I replaced it."

I don't know what fluid RPM Autoworx used when they replaced the master cylinder. Should I enquire with them. Should I consider having the fluid replaced or should I leave well enough alone?

The mechanic said I had goo in my sytem.

Yes, the fluid was full at that time.


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Just keep an eye on your clutch fluid, when it starts to look ucky, change it out with Motul RBF600.

With all the gunk in the hydraulic lines, you are going to need to replace the CSC before long.

Thanks, will do.

Thanks.

Soon = next 500 miles?

or

Soon = next 5000 miles?

Personally, I flush my clutch fluid every other oil change (6000-10000 based on most people’s maintenance schedule). My suggestion is always sooner the more spirited the driving. I would also add to keep an eye on fluid color in addition to fluid capacity. If that stuff is dark brown or has crap sitting in the bottom of the reservoir, change it out! May not need to flush at that instant, but putting some new fluid in the reservoir helps, IMO.

As for how soon I would change the actual CSC, if I were in your shoes I would get it swapped out ASAP.

So the beauty of the clutch system is that it's a small one and rather fool proof until it is not.

I mean fluid quality will be the first giveaway. Overall for this car FLUID QUALITY is the rule you must go by in other to catch these issues ahead of time.

The issue with the clutch is that damn black rubber hose feeding the master, time and time again it have been documented of their deterioration.

Hit up Mike Upton on FB he sells a clear hose intended for brake fluid that wont deteriorate. After the hose you should bleed the entire system and test.
With the new hose and fluid you might save the concentric slave.

The main reason why you had an issue with the clutch at such an early mileage is because this car sat, for a while. This sitting just turned that hose into jelly and that Jelly killed your MC since it's the closest to the reservoir.
Your slave might be OK since most of the fluid in the line was clean and the system usually uses the oil that is past the pump to move the slave and this oil for the most part was clean. Bleeding introduces the old oil for a bit but clears up so again I think your slave will be ok for now.

It wouldnt surprise me if you kill another pump by the time you kill the slave.

That is good advice and I will try to follow it. I am going full synthetic every 5000 miles at this point.

• Does ASAP mean after I return to Utah in 2 months and 15000 miles?
• Or does ASAP mean do ahead and continue through the Tail of the Dragon and Blue Ridge Parkway and have the parts sent ahead from zSpeed to a good mechanic North of here in a 1000 or 2000 miles.
• Or does ASAP mean wait here in Charleston for zSpeed to get the parts and find a mechanic who will do the repairs before going a 100 miles further?

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I know half of it is unobtainium now but replacing both parts with Tilton pieces fixed all my clutch hydraulic woes. Nowadays the recommended solution is a zspeed cmak kit and new oem master. I'm fortunate I did design work for GTM back in the day and have a Tilton racing master and slave bit you can't get the parts anymore. Does anyone make the aftermarket master cylinder conversion kit anymore?

One other thing you can do. Wrap the clutch hose down by the exhaust with insulation. The heat coming off the exhaust can and will boil the fluid with hard driving. It's one of the things track rats do.

Check with Ryan at RJM Performance. He carries a Tilton HD Clutch Master Cylinder for the 370Z. IMHO the most fail-proof combination is:

1. ZSpeed CMAK
2. ZSpeed insulated clutch line
3. RJM Tilton HD Master Cylinder
4. RJM clutch pedal assembly
5. High quality DOT4 fluid (e.g., Motul RBF 600, ATE TYP 200, Castrol SRF)
6. Bleed the clutch regularly ... at least once per year.

Thanks for everyone's help so far.

I have driven from Savannah to Charleston then up to Greenville, SC. The clutch fluid reservoir remains clear.

Let's see what we know and what we don't.

We know that...

• The clutch, seemingly, worked fine from 28 to 38k miles.
• The clutch pedal then started returning with progressively less vigor over a week or two.
• Soon the pedal started sticking a few inches from full return.
• That when bled, black gunk was found in the system and the pedal would not return at all.
• Since the master cylinder was replaced with OEM parts, the clutch started behaving pretty much as before.
• That Joe at zSpeed does not have the parts he needs to ship a slave relocation kit, but he expects them soon.
• The fluid is pretty much perfectly clear after 2 days (700 miles) of driving. Around Charleston involve lot's of stop go and clutch use.

We are pretty sure...

• That the previous owner replaced the OEM clutch "with a competition clutch and billet flywheel" sometime between 10 and 15K miles "because it was slipping" and "I didn't like the clutch."

I believe this because the previous owner had little reason to lie as it would not make the car more sellable. I also have reason to believe that he followed this forum to some degree at least when the car was newish.

We don't know...

• If the slave or master cylinders were addressed or to what degree when the clutch was replaced.
• What clutch and flywheel were purchased and installed.
• A hundred or so other little factoids that would be nice to know right now.

My plans with ZiZi running reliable and strong would be to work my way through the Nantahala National Forest to the Tail of the Dragon, then slowly up the Blue Ridge Highway w/side trips while making my way toward DC.

My choices seem to be...

• To stay here, while waiting for zSpeed and/or others to get the parts needed and search for someone within a 5hr radius to fit me into their work schedule and do the installation.
• To proceed gingerly forward along my current route, nervous as a cat, watching my fluid color while waiting for Defcon 5 and becoming broke down in the heart of Deliverance country, USA. "This river don't go to no Aintree." And try to arrange CSC relocation as soon as I get parts and find a place along my route.
• Put her top down, light a phatty, turn off VDC, rev it and drop the clutch. F*** Thelma. F*** Louise (if she'd have me). And go full bore, caution to the wind until I launch her into a river canyon or find myself back in Salt Lake.
• Some nuance prudently in between the aforementioned options.

Further speculation and advice would be appreciated.

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It may be going and slowing down a lot on the Parkway. If you do the speed limit. It will be a 2 day drive to do the whole thing. :driving:

Yup, I was figuring on about a week to 10 days from here to DC. :icon17:

Are you guessing the slave will be toast long before then, given what we know?

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I think it's 50-50. It could have been just a bad master cylinder that wasn't changed with everything else when the clutch was changed. Or the CSC could be failing and took the master cylinder out first.