JSMCO

2005 350Z 133,000 miles MT

Just replaced the clutch master cylinder and slave cylinder with new OEM parts and deleted the clutch damper using the Sikky line. We bench bled the master before installing, and then gravity bled the entire system, about 3/4 pint of fluid used for the gravity bleed. The rod on the master we left as it came in the package, with about 3 threads showing inside the U shape, same as on the one that came out. Then followed the FSM bleeding procedure, pump pedal 5 times and hold, open and close bleeder, release pedal, wait 5 seconds and repeat. We did this about 20 times, always keeping the reservoir topped, and using Motul 600 fluid. There are no air bubbles. The clutch doesn't feel like it has any pressure at all until the pedal is almost down to the floor. The push rod on the slave doesn't seem to move very much when the pedal is depressed, but it doesn't give back any of it's slight movement while the clutch pedal is depressed so we don't seem to be losing any of the pressure we have. Not sure what to try next? Loosen the nut and adjust for more threads showing? Less threads? Something else?

Any suggestions would be greatly appreciated!

icer5160

iTrader: (4)

Let the vehicle sit overnight. Then follow FSM procedure another 20-30 times. Also, double check your Sikky Line banjo bolts, make sure there’s no fluid weeping. Make sure to pump the pedal rapidly, this is a must to ensure adequate pressure is built up to push out the air.

The fluid can become aerated, letting it sit gives time for the small bubbles to settle. I’ve never had any luck gravity bleeding myself.

Before bleeding again, you can try adjusting the rod depth for a longer stroke. But based on your description, you should be ok with the current setting.

Last thought. If the Teflon lining on the Sikky Line was damaged during the install, then fluid could be leaking internally, this would have symptoms like you’re seeing.

Good Luck!
-Icer

OldManZ350

iTrader: (23)

Even after you bleed it, then pump the peddle about 10-20 times and see if you have peddle then....... I have to do this every time.

JSMCO

Thanks very much for the input.

OK, after the car sat for almost 24 hours, we tried pumping again, no difference at all. We adjusted the pedal stroke to be longer and then pumped the heck out of the pedal, probably 20-30 times. Opened the bleeder, closed it and kept pumping. Repeated process several times. Just when we thought nothing was going to work, all of a sudden the pedal firmed up. Opened the bleeder and much different behavior, the fluid whooshed out and was pretty foamy looking. We did about 10 more cycles of pumping and opening the bleeder until all the bubbles were gone. Adjusted pedal back to have about two threads showing in the U. Right now it's still up on stands for a couple other minor issues, but will report back once it's down and has been driven on whether there is any noticeable improvement in clutch performance. It sat overnight so will probably do another couple rounds of pumping and bleeder cracking just for good measure.

One item to note if you buy the Sikky line. The banjo bolt that threads into the master cylinder was too long and did not seal properly. We cut a few mm off the end of the bolt and then it sealed fine. This was noticed before installation so it was not the cause of the bleeding issues. The bolts Sikky sent us were approximately 20mm length. (From bottom of head to end of bolt) They were the same as the original banjo bolt for the slave. The one for the slave was fine but for the master a 15-16mm length would have been correct. For reference, the bolt is an M10 x 1.0 size and thread pitch. Whether or not one can be found that's a shorter length "from the factory" I don't know, it seems like the 20mm is pretty standard length.

icer5160

iTrader: (4)

Hey JSMCO,

Glad to hear you were finally able to clear some of the trapped air! Please do provide some feedback about the Sikky Line and clutch damper delete. I'm curious to get your before and after opinions on it. What clutch and flywheel combo are you running with right now?
Cheers!
-Icer

JSMCO

My daughter bought the car from a private party and he said that a new clutch had been installed by the previous owner but I don't know any details on brand, etc. I believe the master, line, and slave were all original.

Got everything buttoned up and took it for a short test drive. There is a noticeable difference in the feel when the clutch engages. It feels smoother, once the engagement starts there is far less "chatter" (best word I can think of) than before and it just seems to catch much faster. The actual shifts feel about the same. We'll see if some of the issues she was having when she drives it hard and hot are alleviated by the insulated steel line. (Not wanting to go into gear, etc.)

I have a feeling the pedal might still stick halfway up sometimes but that feels more mechanical to me than hydraulic, I just think the way the pedal is designed with the spring and the weird tensioner lends to it sticking.

So, one of the RJM pedals may be in her future.