Drivetrain Questions and info regarding transmissions, clutches, etc.

Clutch sticking in 06 G35

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  #46  
Old 05-26-2012, 06:37 PM
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I just got back from the track yesterday and on my last run my clutch pedal got stuck on my launch so i got worried as *** obviously lol... But im going to preform this procedure and hopefully it should be good! I can only imagine how black my clutch fluid is lol


http://www.youtube.com/watch?feature...v=gBbsy0LjUvE#!
 
  #47  
Old 08-18-2012, 06:15 PM
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THE FIX for Sticking Clutch Pedal in G-35 Coupe

I have an 05 Coupe and I finally found the fix for this problem
-
Problem - Clutch pedal sticks and must be lifted with foot on hot days when driving in stop and go traffic.

Cause - The clutch fluid is boiling.

Analysis - Fluid will boil at anywhere from 250 degrees to 600 degrees depending upon the type of fluid and how clean it is. (Racing fluids typically boil at a higher temp, but they absorb water faster. That's why road racers change their brake fluid before every event.) Fluid is hygroscopic (absorbs water) so the older it is the more water and contaminants it absorbs, and the lower the boiling point. The flex hose to the slave cylinder is very close to the catalytic converter, and the temp on a cat is typically 500 degrees, and can approach 900 degrees. On a hot day in slow traffic, the cat cooks the fluid in the line. When it boils, you have vapor in the line. That's what makes the clutch pedal "stick." This gets worse the longer you drive the car on a hot day. You drive long enough, more and more vapor bubbles build up in the line, and you'll lose the clutch entirely. Replacing the slave cylinder, as some have done, will help because you have clean components and fresh fluid, but it will not likely solve the problem long term.

Solution - Drain the clutch fluid, remove the left front wheel and tire and the fender liner. Disassemble and unclip the clutch hard line and flex hose where it's mounted to the chassis and move it away from the cat. Reassemble, and then thoroughly flush the clutch master cyl, clutch lines and slave cyl by pumping fresh fluid through the system and bleeding using the bleeder on the slave. Have someone push the clutch pedal while someone opens the bleed screw underneath the car. When the pedal is down, close the bleed screw. (You will have to lift the pedal with your foot each cycle.) Repeat and replenish the fluid reservoir until the fluid is clean coming out of the bleed screw. You'll probably go through most of a 12 ounce can of fluid. Use a high-quality DOT 4 fluid, although Motorcraft DOT 3 is good. (Racers use it in some applications to save some money over racing fluids because of its high boiling point and it's less hygroscopic.) I drilled a small hole in the chassis and attached the line in its new location with a wire tie. I slit an old fuel line and wrapped it around the clutch line to keep it from chaffing on the chassis.

Comment - I've struggled with this in my G-35 for years. I'm an ex racer and have a lot of experience with brake fluid boiling problems on short tracks like the Club Circuit at Sebring in the summer, so I quickly figured out the cause. The fix was harder. I tried flushing the clutch hydraulics, using racing fluid, and insulating the clutch line. All helped, but none fixed the problem completely. Moving the line away from the cat did. I performed this fix this spring, it's now late August, and I've had no problems driving the car for an hour in stop and go traffic on 100 degree days. I feel sorry for all those who have struggled with this, especially those that spent money unnecessarily on master cylinders, slave cylinders, pedal assemblies and even clutches. I suspect some with this problem did burn up their clutches. The clutch is hard to modulate and prone to slipping when the fluid boils. I note there are numerous threads on this topic, so those of you more familiar with this forum can spread the word to other threads on this topic. Good luck.

Here's the URL to pics of the fix - http://www.flickr.com/photos/bandbbr...7631145065236/
 

Last edited by wnbrown; 08-19-2012 at 02:00 PM.
  #48  
Old 09-04-2012, 10:05 AM
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^very interesting, but i'm still convinced the oem units are junk.

I know I have a v36 but I am on my 2nd clutch and master/slave at 55k (replace around 23k). Even 1k after being replaced I experienced clutch sticking and I am already have some extra play in my clutch (wearing from clutch sticking/burning episodes) and my slave/master now are completely toast.


I'm going to replace the slave/master with these aftermarket units and just wrap the slave line with extra insulation to address the heat. Hopefully it will solve the issue. I plan on keeping this car for another 4-5 years, so I will report back yearly to confirm that this is a fix.


http://www.zspeedperformance.com/ZSp...ZSPHDSLAVE.htm
http://www.zspeedperformance.com/Nis...er-ZSP2011.htm
 
  #49  
Old 09-11-2012, 05:21 PM
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So my 06 with 56,000 miles is at the dealer now for this issue. 3 years ago (under warranty) the other dealer in town replaced the master cylinder. This fixed the problem until this summer when it started doing it again on hot days. So I took it in and today they called back and said that they think that somehow the master cylinder replacement gave a 'false positive' that the problem was fixed. Said that they probably should have replaced the slave cylinder. And now, due to the problem not really being fixed, the clutch is worn more than it would have. They are recommending a new clutch of course. $1400. Obviously IF I do need a new clutch, it won't be them doing it.

What do you guys recommend for me? I don't know enough about the system to know if that's total BS or not. This service manager I was working with has taken great care of me in the past, and I trust him. But then again he was really just relaying the service tech's words.

Also, before I even had them check it out, I flushed the clutch fluid a month or 2 ago. So my fluid is brand new.

Thanks
 
  #50  
Old 10-03-2012, 05:00 PM
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I mentioned this on another post, but this is a common problem with our cars. Before changing any major parts, try upgrading the oem clutch line with a stainless steel unit. I had the same problem last summer on my boosted G and I destroyed my clutch on a hard launch. After I replaced the clutch and flushed the fluid several times it kept sticking. Someone on here mentioned the clutch fluid line is known to get hot and expand due to its location near an exhaust pipe thus causing mushy pedal feel and sticking. I ordered the SS line from Z1, slapped it on and the problem hasn't come back. Good luck getting your car fixed, hope this ends up being an inexpensive permanant fix.
 
  #51  
Old 01-04-2013, 02:14 PM
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Clutch sticky and popping

I just recently bought a 2006 coupe 6mt and a few weeks later I too noticed that the clutch is sticking and it also does a popping sound if that makes sense. Now that it is winter here the sticky clutch isn't that bad, but it still pops at about the halfway point.

I'm going to try wd40 then if that doesn't work change the hydraulic fluid. Hopefully that will do the trick.
 
  #52  
Old 06-20-2013, 05:01 PM
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Originally Posted by wnbrown
I have an 05 Coupe and I finally found the fix for this problem
-
Problem - Clutch pedal sticks and must be lifted with foot on hot days when driving in stop and go traffic.

Cause - The clutch fluid is boiling.

Analysis - Fluid will boil at anywhere from 250 degrees to 600 degrees depending upon the type of fluid and how clean it is. (Racing fluids typically boil at a higher temp, but they absorb water faster. That's why road racers change their brake fluid before every event.) Fluid is hygroscopic (absorbs water) so the older it is the more water and contaminants it absorbs, and the lower the boiling point. The flex hose to the slave cylinder is very close to the catalytic converter, and the temp on a cat is typically 500 degrees, and can approach 900 degrees. On a hot day in slow traffic, the cat cooks the fluid in the line. When it boils, you have vapor in the line. That's what makes the clutch pedal "stick." This gets worse the longer you drive the car on a hot day. You drive long enough, more and more vapor bubbles build up in the line, and you'll lose the clutch entirely. Replacing the slave cylinder, as some have done, will help because you have clean components and fresh fluid, but it will not likely solve the problem long term.

Solution - Drain the clutch fluid, remove the left front wheel and tire and the fender liner. Disassemble and unclip the clutch hard line and flex hose where it's mounted to the chassis and move it away from the cat. Reassemble, and then thoroughly flush the clutch master cyl, clutch lines and slave cyl by pumping fresh fluid through the system and bleeding using the bleeder on the slave. Have someone push the clutch pedal while someone opens the bleed screw underneath the car. When the pedal is down, close the bleed screw. (You will have to lift the pedal with your foot each cycle.) Repeat and replenish the fluid reservoir until the fluid is clean coming out of the bleed screw. You'll probably go through most of a 12 ounce can of fluid. Use a high-quality DOT 4 fluid, although Motorcraft DOT 3 is good. (Racers use it in some applications to save some money over racing fluids because of its high boiling point and it's less hygroscopic.) I drilled a small hole in the chassis and attached the line in its new location with a wire tie. I slit an old fuel line and wrapped it around the clutch line to keep it from chaffing on the chassis.

Comment - I've struggled with this in my G-35 for years. I'm an ex racer and have a lot of experience with brake fluid boiling problems on short tracks like the Club Circuit at Sebring in the summer, so I quickly figured out the cause. The fix was harder. I tried flushing the clutch hydraulics, using racing fluid, and insulating the clutch line. All helped, but none fixed the problem completely. Moving the line away from the cat did. I performed this fix this spring, it's now late August, and I've had no problems driving the car for an hour in stop and go traffic on 100 degree days. I feel sorry for all those who have struggled with this, especially those that spent money unnecessarily on master cylinders, slave cylinders, pedal assemblies and even clutches. I suspect some with this problem did burn up their clutches. The clutch is hard to modulate and prone to slipping when the fluid boils. I note there are numerous threads on this topic, so those of you more familiar with this forum can spread the word to other threads on this topic. Good luck.

Here's the URL to pics of the fix - http://www.flickr.com/photos/bandbbr...7631145065236/
Has anyone done this yet? I am pretty adept at working on my car. I mostly understood what was done here, but I haven't been under my car for a while so I was wondering if anyone had a link for a step by step with pics? I saw the pics in the link, but they weren't very descriptive. I'm not sure if there has been a DIY on this yet...But maybe someone wants to put one together being that this is such a common problem...
 
  #53  
Old 08-24-2014, 05:56 PM
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I too am looking to do this fix and would like to see some pics
 
  #54  
Old 08-25-2014, 09:58 AM
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Everything in my original post about boiling the clutch fluid is good info on this problem. However, I have since discovered that re-routing the clutch line helped a great deal, but did not completely solve the problem. After several weeks the fluid would absorb enough moisture, the fluid would again boil and the clutch would stick on really hot days in slow traffic.. Thoroughly flushing the clutch hydraulics with fresh fluid always solves the problem for a while, but the fix doesn't last. I concluded that the fluid in the slave cylinder was boiling and fabricated a heat shield for it, but that didn't work. The slave cyl, which is in a dead air space, is absorbing heat from the bell-housing it's mounted on and radiant heat from the exhaust and catalytic converter.
I finally resorted to a racer's brake-cooling trick, and I haven't had problems since. I ran a two-inch cooling-air tube from the front of the car, all the way back to the clutch slave cylinder. I used some old swimming-pool vacuum hose up front and a flex 2-inch exhaust tubing near the exhaust and catalytic converter. A single length of two-inch diameter wire-wound silicone tubing would have been better. It can handle the heat, and it's lighter than the metal tubing. (I did this on a weekend, and the only place that carries the silicone tubing I needed was closed. )
The routing is complicated, and sorry I didn't photo document. I raised the car, removed the LF wheel and tire and temporarily removed the plastic fender liner and some foam bumper filler for access. I cut a two-inch hole in the plastic panel that's behind the small far left grill. The hose runs from behind the grill, thru that hole, threads thru some suspension and to the clutch slave cylinder. I spent a lot of time routing to ensure the hose and tubing didn't interfere with the suspension, tires or wheels. In places near the exhaust, I used metal wire ties (plastic will melt) to secure the tubing. I also wrapped the metal flex-tubing near the exhaust with fire-proof insulation to keep it cooler. This was probably unnecessary.
Now whenever the car is moving, even slowly, air from the high-pressure area in front of the car travels down the tube to cool the clutch slave cylinder. Most racing cars use this technique to cool brake calipers and rotors to prevent the brake fluid from boiling.
Hope this helps, and next time I've got the car in the air, I'll try and photo-document the fix. So far this summer, I've had no problems and I've had the fix in place since February without flushing the fluid. I wonder if Infiniti fixed this design problem with the G-37 or if they even know about it. From the posts I've read, the dealers don't, and they're making a lot of money with ineffective fixes.
 
  #55  
Old 08-25-2014, 07:41 PM
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Hey thanks for replying!!!

After reading your first solution post I decided to go with this:
http://www.ebay.com/itm/111210428347...84.m1423.l2649


Do you think that would work instead of re routing the clutch line?

Also, If I re-route it, is there no wrong or right? too long ss line, vs too short? as long as it's moved away from the cat ?

This new thing with the cooling vent tube to the cylinder is awesome, I'm very excited for pics of that.

Do you think if I did the cooling vent tube along with that $40 part on ebay it'd be good to go?

I barely drive my g35, just on weekends, but I'd really love to have it working optimally.

I've had my 2005 sport coupe for almost a year, the clutch was toast when I got it, could barely get it into gear with engine started when cold.

I bought a brand new OEM nissan clutch kit and flywheel, had them installed, still clutch was so difficult to shift smoothly at low rpms, like leaving a stop light. I searched and from what I found, I had had the clutch fluid flushed. The clutch felt pretty good after that.

But still had the sticky clutch pedal problem. This last weekend I was having the problem. I did more research on forums and it made sense, it only does it when it's really hot out and after I've driven for about a hour. I had done wd-40 on the pedal a couple times and thought it worked, when in actuality it seemed like it worked because the fluid had cooled.

As far as engine mods, I've just done ztube, HR y-pipe, and new spark plugs. I've just bought MREV2, 5/16 spacer kit, and a PCV valve.

I'm waiting to do the install until I've got a plan and can tackle the clutch problem as well.

Going to get my fluid flushed again afterwards

looking forward to pics / reply
 

Last edited by g35.silversurfer; 08-25-2014 at 08:07 PM.
  #56  
Old 08-25-2014, 09:15 PM
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Sticking Clutch

I've been fussing with this for years, and if I had it to do over again, I would go straight to the two-inch cooling tube to the slave cylinder, then if I still had the problem, I'd also reroute the clutch line. I did it backwards, and would do it differently now based on what I discovered. I used the original hard and flex lines when I rerouted, I didn't change the length.
I spent a lot of time under the car exploring options. I thought about buying a longer hard hydraulic line and radically rerouting it, but opted not. The only way I could see to route a hydraulic line far from the cat meant drilling holes through the frame rail or routing the line under the frame rail. You don't want fuel or hydraulic lines underneath and unprotected by the frame rails. (You only need a short piece of flex hydraulic line between the chassis and slave to allow for engine/tranny movement relative to the chassis under acceleration.)
I'll try and take a couple of pics in the next week. Consider my solution a prototype that works. I would do it slightly differently again. Materials might be tricky to find locally, I suggest pegasusautoracing.com, they have a wide selection of insulators and tubing. You might try their two-inch red/orange silicone. It's rated at 500 degrees. Cats routinely hit 900 degrees, but it might be OK if it's away from the cats (difficult) and insulated. Perhaps my use of metal flex exhaust tubing near the cats wasn't such a bad idea. The only reason I insulated the metal tube was to reduce heat absorption from the cats into the air flowing through the tubing.
Hope this helps, and good luck.
 
  #57  
Old 08-26-2014, 09:09 AM
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Dealers are definitely making money off ineffective fixes as wnbrown noted. I told the dealers about this once a little while back and they immediately wanted to swap out my clutch and flywheel for about $1200. No thanks, especially if the problem is still going to be there afterward.

- DM
 
  #58  
Old 08-29-2014, 10:09 AM
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I just popped the hood to take a gander of where I'd put this cooling hose, I'm not exactly sure what specific area needs to be cooled.

I also looked down and see what might be that $40 ebay part already installed?


or is that stock looking?
 
  #59  
Old 08-29-2014, 11:01 AM
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here's a better pic:
 
  #60  
Old 08-29-2014, 07:07 PM
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would high flow cats not get near as hot and be a problem solver as well? or is there just too much heat getting to the slave cylinder from elsewhere too?
 


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