Nabush

Hi,

I'm from France, sorry in advance for my mistakes

A few weeks ago I installed a JWT Clutch/Flywheel Combo + HD CSC and HD Master cylinder form Zspeed.

I use my car a lot on the track, 15 days ago i went to Le Mans where i lapped 80 laps.

I saw quickly that when i was above 6000 rpm my clutch pedal started to drop on the floor... At 7500 rpm the pedal is half way of the travel... Like if there is a depression/vacuum in the circuit...

My clutch pedal is correctly set up, the system is correctly bled. The pedal is firm and works perfectly. In normal driving you can't see anything wrong...

I don't think there is a leak on the slave cylinder cause the tank level does not drop. But after the 80 laps at Le Mans it became grey with particles in suspension.

Zspeed said that it could be a defective pressure plate... That in the high rpm range the spring reverse due to centrifugal force... But i'm quite sceptical because all my clutch system is new...

In neutral the phenomenom is the same, but a bit less.

Here are some pics of my CSC on place...

https://www.dropbox.com/s/8mzi6gnpi0...504_123519.jpg

https://www.dropbox.com/s/utw47fmotp...504_123530.jpg

Thank for your advice.

icon420

wish i could help buddy thats a tricky one

travlee

iTrader: (8)

funny story.... i have the zspeed slave and wilwood master. recently my pedal has about an inch of play before i start getting pressure on it, the pressure is consistent and firm, and rarely getts a little mushy, but corrects within a couple minutes. when i contacted zspeed about it he told me that he thinks it is out of adjustment or air in the lines. i also have the floating particles and he told me that is fine clutch dust somehow getting in there and not to worry.... but the factory didnt do that til i went out. i just swung by nissan and they told me that they could adjust the clutch some and do a fluid swap for $225, i am just not convinced that is going to resolve the problem

Nabush

Hi,

Before the zspeed i had particles in suspension too in the fluid tank. But my stock csc bellows was torn...

One thing i didn't put back was the heat shield protection around the hoses. I will put it back to see if it's not a problem caused by the heat of the HFC in the high rpm range. But since the HD hoses are reinforced i don't believe in that...

I test drove the car yesterday after the increase of the dead zone of the clutch pedal, and it seems the pedal dropped a little less, not very shure...

travlee

iTrader: (8)

well i got to looking at mine and the shop half assed the master install, instead of routing the line along the factory lines they dropped it down the engine bay and it was sitting about 2 inches away from the header... i went up there and laid into them, needless to say they are going to re-run the line and i am providing the Motul RBF600 for them to use instead of cheap DOT 3 stuff, since i was so close to the header i boiled the fluid and it is breaking down

Nabush

Not the case for me, i routed the lines like the factory line (need to remove splash gard). But the line at the closest is at about 15-20cm from the HFC...Perhaps it´s too close without heat protection...But i doubt it, cause even at 4000 rpm it can be very hot in full trothle, and in this rpm range no problem.

travlee

iTrader: (8)

yeah i have test pipes so i prob have more clearance than you, i am hoping by rerouting mine and changing the fluid i will be good. motul has a fluid that handles heat up to 617 degrees fairenheit / 325 celsius

Nabush

Yes the Motul RBF660.

Personnaly for the Brakes and clutch i use RBF600, which is to change every year, instead of 6 month for the 660...

NMB

iTrader: (4)

+1
and I recently ordered the Zspeed Wilwood Master Cylinder.

HK350 Z

Called Joe and got my answers...

ROCA Z

iTrader: (1)

80 laps its a lot of stress on the clutch. Even if you bleed and use top of the line product there is a breaking point... Correct me if wrong, but in the pictures everything is saturated with fluid... Even the lines have an oily look to them. Take all out find the problem ... It's lots of work but hey....

ZSpeedPerformance

iTrader: (71)

There is no fluid on anything and the slave is fine, What you see on the front of the slave shaft is assy lube from the slave, The sleeve that the release bearing is attached to is lubed when assembled so it glides easily on the shaft.

If he is still having issue with pedal feel it sounds like it is an adjustment issue at the master cylinder.