Clutch Getting Stiff In Hot Weather - MY350Z.COM - Nissan 350Z and 370Z Forum Discussion

Notices
Engine & Drivetrain VQ Power and Delivery

Clutch Getting Stiff In Hot Weather

Old 12-01-2018, 11:36 PM
  #1  
350z_Lam
Registered User
Thread Starter
 
Join Date: Dec 2015
Location: California
Posts: 16
Thanked 0 Times in 0 Posts
Default Clutch Getting Stiff In Hot Weather

I'm beginning to notice some characteristic changes in my clutch pedal in relation to the outside atmospheric temperature. I've noticed in hotter weather above 80F (hence mostly during summer) my clutch pedal becomes really stiff and very hard to press. It progresses to get worser the longer the drive is too on a hot day. It feels like pressing a stage 3 clutch at times. But in colder weather however, it becomes light as a feather again and feels buttery smooth to press down. Is my hydraulics going out? Should I get new master/slave cylinder? What's going here?

Some info on how I drive; I usually modulate and feather my clutch pedal a lot in slow zones, especially like in parking lots. Is it due to this constant pumping action of the clutch that creates the clutch fluid to heat up faster and lose strength to push the cylinder? That's why it feels stiff and bubbly? Like fluid molecules expands and gets thinner when it gets hot so it loses its strength right? Also I notice while feathering the clutch especially on an uphill I can really really really start to feel the stiffness and sponginess even more than on a flat surface.

Last edited by 350z_Lam; 12-01-2018 at 11:37 PM.
350z_Lam is offline  
Old 12-02-2018, 04:03 AM
  #2  
BluestreamDE
Pay it Forward
 
BluestreamDE's Avatar
 
Join Date: Mar 2016
Location: South Carolina
Posts: 1,220
Thanked 286 Times in 231 Posts
Default

When is the last time you did a flush of your clutch fluid? It could be that.

I would also check out your slave and master cylinder, as well as all the plumbing involved. May be on the way out.
BluestreamDE is offline  
Old 12-04-2018, 05:00 PM
  #3  
RobVox
Registered User
 
Join Date: Oct 2016
Location: Washington DC
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default

I noticed similar issues with my clutch in hot weather. I took it to a shop I trust and they checked the hydraulic fluid and said it looked ok. They suspected that the issue was hydraulic line expanding as it absorbs heat from exhaust pipes, etc.

So after that I had them replace the clutch line with the Nismo braided stainless version, which helped. I can still notice a change in clutch feel after driving on a hot day for a while, but it is less drastic and annoying than it had been.

Anyway, I agree: getting the fluid and cylinders checked out is a good place to start. Then, if they seem ok, consider upgrading to braided stainless line. Hope this helps.
RobVox is offline  
Old 12-05-2018, 08:26 PM
  #4  
mr. sparco
Registered User
iTrader: (13)
 
Join Date: Dec 2005
Location: Sunny Beaches
Posts: 6,470
Thanked 200 Times in 158 Posts
Default

Flush the fluid, change out the slave cylinder if its a DE, preventative maintenance. Mine had a similar issue then the pedal would not return after releasing, usually occurs on hot days. After the flush everything was good again.
mr. sparco is offline  
Old 12-05-2018, 09:46 PM
  #5  
350z_Lam
Registered User
Thread Starter
 
Join Date: Dec 2015
Location: California
Posts: 16
Thanked 0 Times in 0 Posts
Default

Thanks for the input guys! I haven't done any clutch fluid flush or anything of the sort yet. The car has kept its same original fluids and everything in there for the past 15 some odd years! :O I guess I'm way beyond overdue.
350z_Lam is offline  
Old 12-05-2018, 10:17 PM
  #6  
terrasmak
Super Moderator
MY350Z.COM
iTrader: (8)
 
terrasmak's Avatar
 
Join Date: Jan 2007
Location: Sin City
Posts: 25,389
Thanked 1,070 Times in 786 Posts
Default

Seals are old and swollen, same thing happened to mine
terrasmak is offline  
Old 12-07-2018, 04:16 PM
  #7  
MicVelo
350Z/370Z Tech Moderator
MY350Z.COM
 
MicVelo's Avatar
 
Join Date: Oct 2014
Location: Northern California
Posts: 6,874
Thanked 1,911 Times in 1,389 Posts
Default

Originally Posted by 350z_Lam View Post
I'm beginning to notice some characteristic changes in my clutch pedal in relation to the outside atmospheric temperature. I've noticed in hotter weather above 80F (hence mostly during summer) my clutch pedal becomes really stiff and very hard to press. It progresses to get worser the longer the drive is too on a hot day. It feels like pressing a stage 3 clutch at times. But in colder weather however, it becomes light as a feather again and feels buttery smooth to press down. Is my hydraulics going out? Should I get new master/slave cylinder? What's going here?

Some info on how I drive; I usually modulate and feather my clutch pedal a lot in slow zones, especially like in parking lots. Is it due to this constant pumping action of the clutch that creates the clutch fluid to heat up faster and lose strength to push the cylinder? That's why it feels stiff and bubbly? Like fluid molecules expands and gets thinner when it gets hot so it loses its strength right? Also I notice while feathering the clutch especially on an uphill I can really really really start to feel the stiffness and sponginess even more than on a flat surface.
I can tell you with 90% surety that it's hydraulic in nature. Key is "you still have original fluids". Brake fluid is hygroscopic, meaning it absorbs moisture from the air (and 15 years worth of absorbtion, your fluid is useless by now.) Moisture (H20) doesn't compress and when it's in a brake/clutch system, the heated moisture becomes even more of a problem because the moisture is also trapping air (bubbles) at that point. A stiff pedal is a sure sign of this.

You may find that terrasmak is also correct and you'll require new seals and/or other components where you cannot just replace seals, e.g., master or slave. Check system for leakage before the flush using a power bleeder (or someone in the car mashing/holding down the pedals) to pressurize the system and inspect all components. (Or hopefully, the shop will do this without just blindly doing the fluid change.)

And then, after diagnosing quality/condition of the hardware - and hopefully only thing you need to do - is to swap out all of the fluids. Do both clutch and brakes while you're at it. If you don't have or have access to a power bleeder, you might want to consider either buying one (recommend Motive unit) OR having it professionally done (and the shop will take care of the proper disposal of your old fluids). I say this because the Z hydraulic systems are very sensitive to being properly drained and bled. Air gets trapped in the system and without a power bleeder, you're likely going to run into the dreaded "OK, pedal feels good now" then a few miles down the road, "Ummmm, WTF.... pedal feels like shid...."

Good luck.

Last edited by MicVelo; 12-07-2018 at 04:23 PM.
MicVelo is offline  
The Following User Says Thank You to MicVelo For This Useful Post:
350z_Lam (12-09-2018)
Old 12-09-2018, 12:48 AM
  #8  
350z_Lam
Registered User
Thread Starter
 
Join Date: Dec 2015
Location: California
Posts: 16
Thanked 0 Times in 0 Posts
Default

Hey Mic! Great to see that you are still active on this forum. I always love reading your long and thoughtout responses not only here but in other posts too. You are always the most informative!

P.S. I still havent gotten a chance to bump into you yet in the bay since that last time :P
350z_Lam is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Phenom
Brakes & Suspension
12
07-22-2009 05:50 AM
xebotwinturbo
Southern California
44
06-24-2008 09:43 PM
almond1294
Maintenance & Repair
5
11-21-2007 12:37 AM


Thread Tools
Search this Thread
Quick Reply: Clutch Getting Stiff In Hot Weather


Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: