soft clutch after hard driving???

ClemsonWill · 04-30-2012, 02:02 PM

I'm not sure if this is the perfect place for this thread but I think you track junkies will most likely know what I'm talking about.

I went driving in the mountain with a few guys this past Saturday. We had a great time. But after good stretch of twisties climbing into the mountains I noticed my clutch get spongie. It felt normal until about half way out from the floor where the clutch seemed to go soft. I have heard a number of different theories as far as the pressure plate got overheated, altitude played a role in changing the properties of the fluid, clutch disk overheated, etc. I was curious if any of you have felt something similar to this. We were 5250 ft above sea level and ran the cars hard for about 15 miles up hill.

BTW it was not just my car. The other guy with a 6mt had the same issue but worse.
I'm back at home and clutch is fine now.

Thanks for any suggestions.

Will

wheee! · 04-30-2012, 02:08 PM

Have you upgraded your clutch line to Stainless Steel yet?? Were you doing a lot of shifting or mainly in one gear?

ZMan8 · 04-30-2012, 02:09 PM

Quote:

Originally Posted by wheee!

Have you upgraded your clutch line to Stainless Steel yet?? Were you doing a lot of shifting or mainly in one gear?

^this

wheee! · 04-30-2012, 02:26 PM

Quote:

Originally Posted by wheee!

Have you upgraded your clutch line to Stainless Steel yet?? Were you doing a lot of shifting or mainly in one gear?

also, for $30 at Z1, it is a no-brainer in terms of performance mods....

Jsolo · 04-30-2012, 02:27 PM

Is the consensus that clutch fluid over heated/boiled due to high heat near the clutch line?

wheee! · 04-30-2012, 02:32 PM

The rubber hose may have become soft and expanded with the heat and pressure. Each press of the clutch just bulged the clutch line....

ZMan8 · 04-30-2012, 02:35 PM

Quote:

Originally Posted by wheee!

The rubber hose may have become soft and expanded with the heat and pressure. Each press of the clutch just bulged the clutch line....

replacing clutch line is a cheap mod and should be done if you plan to drive the car hard for extended time.

Jsolo · 04-30-2012, 02:36 PM

To install an SS line, is removal of the bell housing necessary or there's a hard fitting on the outside?

ZMan8 · 04-30-2012, 02:37 PM

Quote:

Originally Posted by Jsolo

To install an SS line, is removal of the bell housing necessary or there's a hard fitting on the outside?

not sure about that, but I think you have to remove the cats for easier access, which can be a pain.

Jsolo · 04-30-2012, 02:42 PM

It's definitely something I will do if/when I upgrade the clutch on the G. Along with the improved CSC. Only 3K miles on the car for now, and no clutch issues to speak of (other than the crappy clutch feel which I resolved with a weaker spring).

I did drive it rather aggressively through a number of different of different roads in NC/TN including TN129 and TN165, NC28, etc.

Good luck to the OP.

wheee! · 04-30-2012, 02:43 PM

You can do it without removing the cats, but it is tight... and the hard fittings are easy to removve. Very simple mod, maybe and hour total from lifting the car to setting it down again....

ChrisSlicks · 04-30-2012, 02:44 PM

It is mostly the fluid, the hydraulic line isn't under anywhere near as much pressure as in the braking system so being SS or whatever isn't a big difference. Upgrade to high-temp brake fluid for the clutch.

The line is directly next to your exhaust, so especially if you upgrade your cats or headers you will need to add extra insulation to the clutch line near where they pass the header.

I beat my car relentlessly on track, with the stock clutch line and never get a soft clutch pedal, I use RBF600 and extra insulation wrap.

ClemsonWill · 04-30-2012, 02:46 PM

Quote:

Originally Posted by wheee!

Have you upgraded your clutch line to Stainless Steel yet?? Were you doing a lot of shifting or mainly in one gear?

No, I have not. I was shifting between 2nd and 3rd a good bit.

ClemsonWill · 04-30-2012, 02:48 PM

Quote:

Originally Posted by ChrisSlicks

It is mostly the fluid, the hydraulic line isn't under anywhere near as much pressure as in the braking system so being SS or whatever isn't a big difference. Upgrade to high-temp brake fluid for the clutch.

The line is directly next to your exhaust, so especially if you upgrade your cats or headers you will need to add extra insulation to the clutch line near where they pass the header.

I beat my car relentlessly on track, with the stock clutch line and never get a soft clutch pedal, I use RBF600 and extra insulation wrap.

Thanks everyone for your input. I was thinking it was the fluid too. I'm about to upgrade the brake system so I will go ahead and do the clutch line and fluid as well. Thanks again.

wheee! · 04-30-2012, 02:51 PM

Good idea. I should have mentioned the fluid too. I replaced all the fluids in my car after the first 5000 km's.

04-30-2012, 02:02 PM	#1 (permalink)
ClemsonWill A True Z Fanatic Join Date: Jul 2010 Location: Charleston, SC Posts: 12,045 Drives: a Civic VP! Rep Power: 445	soft clutch after hard driving??? I'm not sure if this is the perfect place for this thread but I think you track junkies will most likely know what I'm talking about. I went driving in the mountain with a few guys this past Saturday. We had a great time. But after good stretch of twisties climbing into the mountains I noticed my clutch get spongie. It felt normal until about half way out from the floor where the clutch seemed to go soft. I have heard a number of different theories as far as the pressure plate got overheated, altitude played a role in changing the properties of the fluid, clutch disk overheated, etc. I was curious if any of you have felt something similar to this. We were 5250 ft above sea level and ran the cars hard for about 15 miles up hill. BTW it was not just my car. The other guy with a 6mt had the same issue but worse. I'm back at home and clutch is fine now. Thanks for any suggestions. Will __________________ Slightly modded

04-30-2012, 02:08 PM	#2 (permalink)
wheee! A True Z Fanatic Join Date: Sep 2009 Location: Mod Capital of Canada Age: 58 Posts: 7,354 Drives: cars. lots of cars. Rep Power: 40182	Have you upgraded your clutch line to Stainless Steel yet?? Were you doing a lot of shifting or mainly in one gear? __________________ H&R / Stillen / Berk / HKS / Swift / Michelin / UpRev / SPC / Amuse Rep / Seibon / Fringe XVO / TWM / more... My Journal

04-30-2012, 02:32 PM	#6 (permalink)
wheee! A True Z Fanatic Join Date: Sep 2009 Location: Mod Capital of Canada Age: 58 Posts: 7,354 Drives: cars. lots of cars. Rep Power: 40182	The rubber hose may have become soft and expanded with the heat and pressure. Each press of the clutch just bulged the clutch line.... __________________ H&R / Stillen / Berk / HKS / Swift / Michelin / UpRev / SPC / Amuse Rep / Seibon / Fringe XVO / TWM / more... My Journal

04-30-2012, 02:43 PM	#11 (permalink)
wheee! A True Z Fanatic Join Date: Sep 2009 Location: Mod Capital of Canada Age: 58 Posts: 7,354 Drives: cars. lots of cars. Rep Power: 40182	You can do it without removing the cats, but it is tight... and the hard fittings are easy to removve. Very simple mod, maybe and hour total from lifting the car to setting it down again.... __________________ H&R / Stillen / Berk / HKS / Swift / Michelin / UpRev / SPC / Amuse Rep / Seibon / Fringe XVO / TWM / more... My Journal

04-30-2012, 02:44 PM	#12 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 653	It is mostly the fluid, the hydraulic line isn't under anywhere near as much pressure as in the braking system so being SS or whatever isn't a big difference. Upgrade to high-temp brake fluid for the clutch. The line is directly next to your exhaust, so especially if you upgrade your cats or headers you will need to add extra insulation to the clutch line near where they pass the header. I beat my car relentlessly on track, with the stock clutch line and never get a soft clutch pedal, I use RBF600 and extra insulation wrap. __________________ Hotchkis ARB \| Stillen CAI \| Art Pipes \| Berk CBE \| Stillen AP Racing Brakes \| AE Performance Oil Cooler \| BC Racing ER Coilovers \| Doran Control Arms

04-30-2012, 02:27 PM	#5 (permalink)
Jsolo Track Member Join Date: Dec 2011 Location: chicago Posts: 783 Drives: '12 G37 6MT Rep Power: 15	Is the consensus that clutch fluid over heated/boiled due to high heat near the clutch line?

04-30-2012, 02:36 PM	#8 (permalink)
Jsolo Track Member Join Date: Dec 2011 Location: chicago Posts: 783 Drives: '12 G37 6MT Rep Power: 15	To install an SS line, is removal of the bell housing necessary or there's a hard fitting on the outside?

04-30-2012, 02:42 PM	#10 (permalink)
Jsolo Track Member Join Date: Dec 2011 Location: chicago Posts: 783 Drives: '12 G37 6MT Rep Power: 15	It's definitely something I will do if/when I upgrade the clutch on the G. Along with the improved CSC. Only 3K miles on the car for now, and no clutch issues to speak of (other than the crappy clutch feel which I resolved with a weaker spring). I did drive it rather aggressively through a number of different of different roads in NC/TN including TN129 and TN165, NC28, etc. Good luck to the OP.

04-30-2012, 02:51 PM	#15 (permalink)
wheee! A True Z Fanatic Join Date: Sep 2009 Location: Mod Capital of Canada Age: 58 Posts: 7,354 Drives: cars. lots of cars. Rep Power: 40182	Good idea. I should have mentioned the fluid too. I replaced all the fluids in my car after the first 5000 km's. __________________ H&R / Stillen / Berk / HKS / Swift / Michelin / UpRev / SPC / Amuse Rep / Seibon / Fringe XVO / TWM / more... My Journal

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