Zergfest

iTrader: (1)

Fellow Z Drivers,
I recently visited a race track once again and encountered a new problem. After a few laps glutch pedal stopped majority of its movement and stayed "almost floored", raising up by under 2 inches. This however did not have any real effect on actual driving, as in glutch held gear and didnt slip, and when pressed the glutch allowed my to change gear without any issues.


Could some rubber tubing expand because of heat? After cooling the car off for a good 30mins glutch worked just fine after. Everything relevant to glutch is stock. Anyone else heard/experienced anything similar? I am planning to change the tubes to metal versions (dont know the word for this, sorry) eventually, maybe next year.
Sorry for my english, but I think u get my point..



EDIT: What made this weird is that I only drove like 3 laps before the problem started. The track is not very long, maybe 1,5miles. Water temp was normal and had no heating issues before.

Zerg

travlee

iTrader: (8)

try changing the fluid first, if that doesnt resolve your issue then you may need to change the clutch master and slave cylinders

Zergfest

iTrader: (1)

Thanks for your reply.


I'm going to change the fluid and part of the original tubing soon, but will have to wait untill august for next trackday.

dkmura

iTrader: (64)

Zerg- excessive heat can develop if you were changing gears often and not rev matching on the downshifts. That puts more strain on the syncros to keep up, and heats up the gearbox faster. Before you drain the gearbox, start by opening the fill hole (on the PS of the box) first. Nissan has designed it so you can put your finger into check the gearbox lubricant level. It should be up to the bottom of that hole and if you can't feel it, there's just not enough lubricant in there. Make sure the car is level on jackstands to get an accurate reading.

Also, check to make sure you're using a good quality gearbox lubricant that meets Nissan's specs. Here in the States, a high performance synthetic lubricant like Redline MT85 is a good choice for high-performance cars like the Z.

Zergfest

iTrader: (1)

Hi again DK.

Yea I'm aware of revving when downshifting - this is also quite necessary on the track I tend to drive: you have changes in altitude as well as some "fast corners", where accidentally locking rear wheels with gear changes can result catastrophy. This combined with 1-10yards of space off track before wall.

Not gonna drain the gearbox as I just got the Redline you mentioned set up a year ago - confident that cant be the case. Clutch however has way too much fluid in it (above max level) and I have no knowledge when it was changes - if ever - so gonna go for that. Separate fluids, aint they.

The pedal is also quite stiff, has been like that always. Drove another Z a while back and the pedal was much more soft to press. Maybe the excess liquid causes some of that too - will see.

dkmura

iTrader: (64)

The clutch pedal on my Z is also pretty stiff. I've driven others that have a much softer feel, but I prefer a firmer feel anyway. If you have a LOT of fluid in the gearbox, you should at least drain it back to the full mark. A little extra won't hurt, but too much lubricant adds drag to the moving parts and can't be good for their operation.

As for the rubber hoses with your clutch master, they cannot be the cause of your low clutch pedal. Unless they're damaged in an accident, they should last the life of the vehicle. I tend to agree with travalee on the slave cylinder being the most likely culprit. Replace that first, and if the problem persists, start looking at the clutch master.