Chronic clutch hydraulic problem, damper?

[piste]

1997 SE OR about 150K miles...original owner. I have a chronic clutch hydraulic problem that resurfaces at the start of the past four winters. Outside of the winter I NEVER take trips longer than my work commute which is about 30 minutes of mostly stop and go. In the winter I ski at a mountain that is about an hour away from my house...most of it highway running at 70 MPH give or take. Every year for the past 4 years I lose clutch pressure after my first trip or two to the mountains. This has happened since replacing the clutch itself in Oct 2007. Master and slave cyl replaced in Dec 2007 got me thru that winter. Nov 2008 problem resurfaced...solid bleeding of the system got me through that winter. Dec 2009 problem resurfaced....replaced master and slave again along with rubber hose to the slave...got me through rest of that winter. Drove to the mountain a week ago Sunday and by Friday lost clutch pressure. Only parts left to try replacing is a couple more tubes and the clutch damper. No visible fluid leaks anywhere. Anyone have any thoughts? And what is the purpose of the clutch damper? I'm thinking that is a strong suspect.

[rgallant]

Just a question so I understand the problem> You drive all year with no problem even though you have short trips, once the weather gets cold and you drive any distance the problem occurs ? I am assuming the usual pump the clutch a few times brings up the pressure.

 

It sounds like you have a leak somewhere, but only being cold weather that seems unlikely. If you bleed the system in the winter does the problem go away or re-occur ?

[piste]

Just a question so I understand the problem> You drive all year with no problem even though you have short trips, once the weather gets cold and you drive any distance the problem occurs ? I am assuming the usual pump the clutch a few times brings up the pressure.

 

It sounds like you have a leak somewhere, but only being cold weather that seems unlikely. If you bleed the system in the winter does the problem go away or re-occur ?

 

Answer to your first part is..yes that is correct. So the only conditions that are different when the problem get triggered are longer trips..which means higher temps under the hood...and cold weather. But there is VERY VERY high correlation with the longer trips...as opposed to the cold ambient weather. Pumping the pedal brings pressure back up...but not for very long....need to pump it up every 20 minutes or so to get good shifting. I'm thinking the higher operating temps under the hood during the longer trips is this trigger...just need to figure out how. Elevated temps would increase pressure of the hydraulic fluid...

[rgallant]

Ok, I understand the problem now, but your engine temp is tossing you a red herring assuming you get up to operating temp going to work the distance and speed difference should not matter, a closed hydraulic system is just that closed. The amount of heat increase from normal engine temp should not make a diff. I will check a few things, it is possible that as a result of the longer distance you shift more causing the problem , BUT I would expect it to occur over the course of several drives during the week.

 

Checking the manual you have 3 possible problem areas, Master, Operating and Damper. You have replaced 2 of the 3, A master cylinder should last for far more than 2 years, I would tend to suspect crap in the lines, damaged lines (bulged) or a faulty Damper as you have not replaced that.

 

However the recommended bleed procedure is to bleed at the operating cylinder and the damper. I would tend to do the damper 1st as it is higher up the lines then do the operating. You should use a lot of fluid, empty the reservoir at least twice each time and examine the stuff that exits for contamination.

 

Check your lines the one that goes to the operating cylinder particularly for bulges or cracks and particularly the operating cylinder (the one underneath) for dust cover damage. You may need some one to pump the clutch while you watch that line to the operating cylinder.

 

I will take a look at mine in the morning and locate the damper and see if it is a possible for it to come into contact with the exhaust.

[piste]

Ok, I understand the problem now, but your engine temp is tossing you a red herring assuming you get up to operating temp going to work the distance and speed difference should not matter, a closed hydraulic system is just that closed. The amount of heat increase from normal engine temp should not make a diff. I will check a few things, it is possible that as a result of the longer distance you shift more causing the problem , BUT I would expect it to occur over the course of several drives during the week.

 

Checking the manual you have 3 possible problem areas, Master, Operating and Damper. You have replaced 2 of the 3, A master cylinder should last for far more than 2 years, I would tend to suspect crap in the lines, damaged lines (bulged) or a faulty Damper as you have not replaced that.

 

However the recommended bleed procedure is to bleed at the operating cylinder and the damper. I would tend to do the damper 1st as it is higher up the lines then do the operating. You should use a lot of fluid, empty the reservoir at least twice each time and examine the stuff that exits for contamination.

 

Check your lines the one that goes to the operating cylinder particularly for bulges or cracks and particularly the operating cylinder (the one underneath) for dust cover damage. You may need some one to pump the clutch while you watch that line to the operating cylinder.

 

I will take a look at mine in the morning and locate the damper and see if it is a possible for it to come into contact with the exhaust.

 

Thanks for the dialogue. The correlation between the longer trips at the start of ski season and the clutch failure over the past four years is indeed perplexing. I actually probably shift as much or more during my 30 minute daily commute than the mostly highway trip to the mountains wherein I spend about 45 minutes of the hour without shifting at all. Equally perplexing is that for like 2 of the 4 years a good strong system bleeding got it through the balance of that winter and the following summer. The lines are in good visible shape...no rust or anything and very clean. Irrespective of that...there could indeed be crap in there somewhere. But of course that begs the question of correlating that to the recurrence triggered by the longer trips? For your reference..the damper is actually located up near the master. And ..unfortunately I started down this road with a dealer so that's where it went this morning. Driving it there I had to pump up the clutch system every five minutes or so to create enough pressure to shift for a while. That's what I've been doing since Friday....and so if there were a leak somewhere in the system...one would think the reservoir level in the master would be down a bit. So checked it when I got to the dealer and the master was full up. Implication there is that system loses pressure by fluid leaking back in to the master. could a faulty damper do that ? or at least contribute to that? Or is it more likely a faulty master? One sense I have is that I have more than one problem in the system ..potentially. Also, spoke at length with the head mechanic at the dealer. Our agreed upon game plan is to first replace the damper which is original to the vehicle. If that doesn't do it....only two things left are....replace the lines...which might fix it if there is a contaminant in there that does not seem to get dislodged by bleeding....not very likely...but cheaper than the next step.....which is to replace the clutch!! He said there's an outside chance a fork is sticking in there which MIGHT cause this problem...but he said it in a way that made me think he thought that was a far stretch. BUT....all this problem started in the winter of 2007/2008 after having a (different) dealer put a new clutch in during Oct 2007. So maybe the clutch kit was defective...or they messed up the install? It kills me cuz this Pathy is in GREAT shape for being 13 years old....and I want to keep it many more. Thanks for listening and all thoughts welcome. Praying it's the damper....or that at least that buys me another year or so before I have to put in my 4th clutch...the original being the first.

[rgallant]

Clutch fork is a really long stretch, that would tend to consistent, or may just weird vibration related don't see it though. The only other thought I had was water contamination in your fluid, this will cause the problem you have experienced. You can read up on this on the net it mostly effects brakes, but would have a similar effect on a hydraulic clutch, as I noted above it requires a complete bleed out of your existing system to correct.

 

Good luck, and let us know the end result.

[piste]

Just did some searching and found this short thread...which describes my problem exactly. I'm curious about the statement that dampers are common problem point. Anyone else have any knowledge or experience that corroborates this? My new damper is going in today.

 

http://www.nissanpathfinders.net/forum/index.php?showtopic=25329&st=0&p=465392&hl=clutch&fromsearch=1entry465392

[XSrcing]

This exact same thing just happened to me. I went on a 3 hour drive to Seattle and back with fairly warm weather, the coolant temps were normal, but underhood temps were high (especially at the back near the clutch line). Then it got down in to the teens and I let the truck sit for a while. When I get it the first time, everything is normal, but onces the truck warms up BAM there is a bubble in there. I completely flushed the system with new fluid and it is fine now.

 

My only theory is that the long trip had caused the really, really old fluid (which is hydroscopic) to somewhat seperate: the brake fluid and the water it had absorbed had separated. Then when the temp drop the water froze. After driving, the water unfroze and evaporated causing an air bubble that would occur every time you got the engine warm. All the air bubbles were between the master cylinder and the damper.

 

Sounds a little far fetched, but it is the only theory my friends and I could come up with. So after completely flushing my system of every trace of old fluid (I ran two bottles of fluid through the system) I have no problems anymore.

Edited December 16, 2010 by XSrcing

[piste]

This exact same thing just happened to me. I went on a 3 hour drive to Seattle and back with fairly warm weather, the coolant temps were normal, but underhood temps were high (especially at the back near the clutch line). Then it got down in to the teens and I let the truck sit for a while. When I get it the first time, everything is normal, but onces the truck warms up BAM there is a bubble in there. I completely flushed the system with new fluid and it is fine now.

 

My only theory is that the long trip had caused the really, really old fluid (which is hydroscopic) to somewhat seperate: the brake fluid and the water it had absorbed had separated. Then when the temp drop the water froze. After driving, the water unfroze and evaporated causing an air bubble that would occur every time you got the engine warm. All the air bubbles were between the master cylinder and the damper.

 

Sounds a little far fetched, but it is the only theory my friends and I could come up with. So after completely flushing my system of every trace of old fluid (I ran two bottles of fluid through the system) I have no problems anymore.

 

Interesting. That is kind of consistent with my situation...but my issue is that this has happened EVERY year for the last four years!! Sometimes a good strong bleeding got me through the balance of the winter...including numerous of the long trips that triggered the problem...only to have the problem recur the next winter upon the first or second long trip. Point being...each of the past four years ..when the problem started again...my fluid was a year old at most. So at least for my situation it goes against the theory you propose. Further...some of the years...I'd get on the highway just fine...then after an hour at 70mph or so with ZERO shifting...I'd go to downshift to get off the highway...only to find no clutch pressure...so no water in the line freezing there.

[Alkorahil]

 

My only theory is that the long trip had caused the really, really old fluid (which is hydroscopic) to somewhat seperate: the brake fluid and the water it had absorbed had separated. Then when the temp drop the water froze. After driving, the water unfroze and evaporated causing an air bubble that would occur every time you got the engine warm. All the air bubbles were between the master cylinder and the damper.

 

 

This is exactly what I was thinking. The fluid has abosrbed too much water vapor.

Brake and clutch fluid as mentioned above have high hydroscopic properites - they absorb water molecules from the outside air.

 

What may have happend is there In summer there is more water vapor in the air (humidity), in winder the temps are lower so the water in the fluid will freeze when the temps get low enough adn the system can not create enough hydrolic pressure without pumping the system to get the pressure up.

[piste]

This is exactly what I was thinking. The fluid has abosrbed too much water vapor.

Brake and clutch fluid as mentioned above have high hydroscopic properites - they absorb water molecules from the outside air.

 

What may have happend is there In summer there is more water vapor in the air (humidity), in winder the temps are lower so the water in the fluid will freeze when the temps get low enough adn the system can not create enough hydrolic pressure without pumping the system to get the pressure up.

Interesting...but seems kind of incomplete....but it might be the essence of the issue..or at least one part of it. How did the water...or humid air get into the system without any eveidence of fluid getting out? And irrespective of that...it somewhat correlates with XSrcing's symptoms...but it doesn't correlate with mine at all. Clutch works fine getting to the highway...and after an hour of highway driving clutch fails when attempting to downshift getting off the highway.

[Alkorahil]

Interesting...but seems kind of incomplete....but it might be the essence of the issue..or at least one part of it. How did the water...or humid air get into the system without any eveidence of fluid getting out? And irrespective of that...it somewhat correlates with XSrcing's symptoms...but it doesn't correlate with mine at all. Clutch works fine getting to the highway...and after an hour of highway driving clutch fails when attempting to downshift getting off the highway.

 

 

The fluid naturally abosrbs it from conact with the ouitside air over time. The resevour cap does not make a total/complete seal.

 

Perhaps this will explain better:

http://en.wikipedia.org/wiki/Brake_fluid

 

note: brake and clutch fulid are the same.

[piste]

The fluid naturally abosrbs it from conact with the ouitside air over time. The resevour cap does not make a total/complete seal.

 

Perhaps this will explain better:

http://en.wikipedia.org/wiki/Brake_fluid

 

note: brake and clutch fulid are the same.

 

I understand what you are saying...I have a degree in Chemical Engineering...for what that is worth. But I still do not understand what you are suggesting the "problem" is? Are you saying that the problem is a defective or leaking master cylinder cap? What you propose above is not a result of normal operations of the system.

 

Edit to add: and as I think about it further...even if you were to leave the master cylinder cap off entirely....no matter how humid the air...the density of the hydraulic fluid is such that the water vapor would not be able to transfer from the air and condense into liquid water directly into the hydraulic fluid as water molecules.. Secondly, even if it did.... which it wouldn't...it would remain on the surface of the fluid in the reservoir as it is lighter than the hydraulic fluid and therefore would not be introduced into the closed hydraulic system tubing as a result of operating the master cylinder.

Edited December 17, 2010 by piste

[Nutz]

Did you get the Clutch Damper replaced? If so, did it fix the problem? I don't have the loss of pressure problem you described, but I am starting to get some nasty clutch chatter when starting off in 1st gear. I've flushed the system and bled the slave cylinder with no effect. i just discovered that it has a clutch damper, so I'm going to try to bleed it, and see if it helps. Not sure exactly what the damper is supposed to do or what the syptoms of a failing damper are?

Edited December 26, 2010 by Nutz

[MY1PATH]

The clutch damper Is like a pressure valve It holds a small ammount of pressure in the line after you've released the pedal to reduce chatter from the clutch fork sitting loose. There were some threads on N4W about it and several guys just bypassed theirs with no ill effects IIRC.

[ZombeeXXX]

How many miles on your clutch, nuts? Sounds like wear or oil contamination. Might want to think about rweplacing it.

[piste]

Did you get the Clutch Damper replaced? If so, did it fix the problem? I don't have the loss of pressure problem you described, but I am starting to get some nasty clutch chatter when starting off in 1st gear. I've flushed the system and bled the slave cylinder with no effect. i just discovered that it has a clutch damper, so I'm going to try to bleed it, and see if it helps. Not sure exactly what the damper is supposed to do or what the syptoms of a failing damper are?

 

I just picked up my Pathy yesterday with the new damper installed. Unfortunately I won't know with certainty until at least a year from now if the root cause has been fixed...but I COULD know sooner if it hasn't!! Three years ago this problem began..shortly after putting in a new clutch in the summer of 2007...I lost clutch pressure a few months later...a new master and slave didn't fix it but a good strong followup bleeding got me through that winter. Two years ago lost pressure again...and a bleeding got me through that winter...until LAST year when I lost pressure again ...upon which yet another master and slave didn't fix it but replaced hose #30855 which got me through last winter...until earlier this month when I lost pressure yet again. Only components of the clutch hydraulics NOT previously replaced were the damper and the lines...so in went the damper. If that doesn't do it...I'm going to replace all the lines even though they all look pristine....and if that doesn't do it...I guess it's a new clutch...and if that doesn't do it...

[piste]

The clutch damper Is like a pressure valve It holds a small ammount of pressure in the line after you've released the pedal to reduce chatter from the clutch fork sitting loose. There were some threads on N4W about it and several guys just bypassed theirs with no ill effects IIRC.

 

Interesting...you know I have for a long time had a "noise" that I now believe is this "chatter" you guys are talking about. It's when I'm letting the clutch back out and hitting a bit of gas...and it goes away as soon as the clutch is fully engaged. I'll have to see in the next few weeks if this new damper has eliminated the "noise".

 

ZombeeXXX, In my case...my clutch is just over three years old and has about 30K miles on it. Is chatter a typical symptom of a worn clutch?? ...which mine should obviously not be worn with that mileage/time...but I've not had good luck at all with clutches in this PAthy...Got 70K out of the orig...which I understand is fairly typical...and only about 50K out of my second one.

Edited December 29, 2010 by piste

[rgallant]

You symptoms are not in any way typical of a worn clutch, worn clutches are a problem all the time, and would actually be worse around town where you shift a lot.

[Nutz]

How many miles on your clutch, nuts? Sounds like wear or oil contamination. Might want to think about rweplacing it.

I replaced my first clutch at about 130K, and Im at 230K now. I guess I'm living on borrowed time with this clutch. My old girl spend about 12 years as a daily driver for my wife in stop and go rush hour freeway driving, so I certainly can't complain. I did flush the damper (and slave again) yesterday with my son's help, and its seems to engage smoother starting in first, though I haven't driven it alot in heavy traffic, which is when it usually starts to really act up and get jerky. It feels great shifting through the rest of the gears.

 

Thanks MY1PATH for the info on the function of the damper. I'm not getting any noise from the clutch when it's engaged, so it sounds like the damper is not a likely cause of the jerky engagement in 1st.

 

Piste, I'm completely baffled by your problem. Logically, it has to be a hydraulic issue, not a worn clutch, but since you've replaced the master and slave twice, it doesn't make sense that either of those would be causing the problem. Hopefully the damper was the weak link in the system and its fixed for good.

Edited December 30, 2010 by Nutz

[piste]

I replaced my first clutch at about 130K, and Im at 230K now. I guess I'm living on borrowed time with this clutch. My old girl spend about 12 years as a daily driver for my wife in stop and go rush hour freeway driving, so I certainly can't complain. I did flush the damper (and slave again) yesterday with my son's help, and its seems to engage smoother starting in first, though I haven't driven it alot in heavy traffic, which is when it usually starts to really act up and get jerky. It feels great shifting through the rest of the gears.

 

Thanks MY1PATH for the info on the function of the damper. I'm not getting any noise from the clutch when it's engaged, so it sounds like the damper is not a likely cause of the jerky engagement in 1st.

 

Piste, I'm completely baffled by your problem. Logically, it has to be a hydraulic issue, not a worn clutch, but since you've replaced the master and slave twice, it doesn't make sense that either of those would be causing the problem. Hopefully the damper was the weak link in the system and its fixed for good.

 

Hey,

Yeah I'd say you are doing good with getting 130K and then 100K+ out of the clutches. Clutches are a wear and tear item...and as you allude to...their useful life is very much related to the type of driving. If one is doing nothing but long distance highway driving one might get a couple hundred thousand miles out of a clutch...or more....alternatively if it's constant stop and go traffic the clutch might wear out in 50K miles...or even less!

 

As for my problem...today I did the "longer" distance drive to the local ski mountain that is often the precipitator of the problem each winter season....the clutch seemed to hold up fine and seems to have a much nicer feel with the new damper. I agree that it's a hydraulic issue...but would not rule out the possibility of a compound problem...i.e. two problems existing at the same time and contributing to create very unusual symptoms. In any event....I'm optimistic for the moment but given past experience over the past 3 winters...4 counting this one...I won't know with certainty if the root cause has been resolved for at least another 12 months.

[XSrcing]

Clutch chatter is the jerky engagement you are feeling. It usually happens when you replace a clutch and don't resurface the flywheel. It isn't going to hurt anything and will eventually stop.

 

The damper keeps slight pressure against the clutch fork to stop it from possibly rattling. Though I'm sure a faulty damper can work in complete opposite when broken and absorb any pressure you try to apply.

 

After a thorough bleeding my clutch is working like a champ and it's back below freezing here.