Topic: Clutch question

[kwayne]

Read in Oct 2009 Poular Mechanics a readers question regarding keeping the clutch depressed while stopped. The reader had to replace their slave cylinder on a Truck. His mechanic had said that "this practice might have caused the slave unit to fail. PM responded that "On a more mechanical level,the practice keeps hydraulic pressure on the slave cylinder, shortening the life of the seals. It also keeps the throw out bearing spinning."
Question - is this correct, as I also keep the clutch depressed while stopped.? As the manual tranny's in our cars have hydraulic clutches -Am I decreasing the life of this unit?

[rich71]

when i am at a stop i keep the car in neutral with my foot off the clutch. partly because i get tired of pushing it in at a stop light, but i was brought up to do that as it takes the pressure off the springs and mechanisms hence increasing life.....This was taught to me back in the day when i had pos beaters that i was concerned about a weak, slipping clutch getting weaker....i still do it, i think it can't hurt....not sure about coasting down hill in neutral without the clutch in....seen that done too, but i don't do that....imho, i think it may help. is there proof either way?????? It makes me feel good, so theres my answer.

[Treeman]

I recall this question coming up in Hot Rod Magazine years ago (says the graybeard!).  Their analysis was that it made no difference one way or the other.

[snaponbob]

Shouldn't matter on the hydraulics. But the throw out bearing takes the abuse. Given the very high labor yime to go into the bell housing on the LNF, discretion dictates NOT leaving the car in gear at extended stops (lights, and such). Why tempt fate ???

[Critterman]

Especially if you have a high pressure aftermarket clutch.  It gets heavy!

[lil goat]

There is much debate on this in the motorcycle world as to which is safer as well. Clutch in if you get rear ended you would most likely dump the clutch and stall the bike making it immobile to absorb the shock, same would be true of a car. With it in neutral you would get pushed into the intersection absorbing less shock but getting hit broad side, soooo. who knows from a safety standpoint. Me most of the time I put it in neutral, just easier on my leg, that is even more expensive to fix than the clutch, been there done that.

[Uranium-238]

Uh, I just don't worry about it. I downshift when decelerating, (yes, I rev match) accelerate hard, autocross the car and I still plan on getting a tune. At this point I think the little bit of extra life I'd get by leaving it in neutral when stopped wouldn't be enough to make it worth the trouble.

[snaponbob]

There is much debate on this in the motorcycle world as to which is safer as well. Clutch in if you get rear ended you would most likely dump the clutch and stall the bike making it immobile to absorb the shock, same would be true of a car. With it in neutral you would get pushed into the intersection absorbing less shock but getting hit broad side, soooo. who knows from a safety standpoint. Me most of the time I put it in neutral, just easier on my leg, that is even more expensive to fix than the clutch, been there done that.

MC clutches are very different, as you probably know, than auto clutches. Never liked to hold the clutch lever in too long as even oil bath clutches can heat up and start creeping !!!!!!! THAT'S not fun. Bottom line, it's all about the trade offs.

[sunnygator]

His mechanic had said that "this practice might have caused the slave unit to fail. PM responded that "On a more mechanical level,the practice keeps hydraulic pressure on the slave cylinder, shortening the life of the seals. It also keeps the throw out bearing spinning."

Heard the same things.  In general, I think it's hype created to cover up less than stellar clutches.  Guess what if you use something, it's going to break sooner or later.  Something about the second law of thermodynamics.....but if you ask me these things should be designed so that throwout bearings and slave cylinders can handle being held in at stoplights and stop and go traffic.  Your wheel bearings last how long?  The cylinders in your engine take how much more pressure for how many more cycles?

All that said, I now follow that advice (to go into neutral and foot off the clutch) when I'm pretty sure the stop will be over 30 secs or so......

[Sol Asylum]

My parents taught me to "stand" on the clutch at stops when I learned to drive manual.  Their clutches were doing good if they lasted 80K miles, the pressure plates always wore out and the wear on the release bearing and diaphragm fingers was very obvious.  Being stupid I continued the practice until the clutch on my first car went out.  Being a poor college student at the time I changed the clutch myself and after all the BS that that entailed I though why not try putting it in neutral at the lights.  Based on my personal experience clutches last a hell of a lot longer if you put it in neutral.  I haven't had to change the clutch on one of my own cars since and that is now at well past 170k miles on just one of my rides.

If you understand how the clutch components work its easy to see that if you don't have your foot on the clutch pedal then none of the release components are wearing.  So if you can reduce the amount of wear then logic dictates that things will last longer.

You can stand on the clutch if you want but the only benefit that I saw was that when it came to playing hockey my left ankle was a lot stronger then my right, and those that know how to ice skate will understand that benefit.

[DRGNSLR]

FWIW #1  - I agree with Sol Asylum:

I almost always shift into neutral w/ no pressure on the clutch pedal at traffic lights, drive throughs, etc.  My last standard tranny was a Toyota Supra w/ a turbo engine and that car had 137K on the original clutch and the thing was still as strong as an ox on the day I sold it.  I've also changed two clutches in automobiles used jointly with another driver who always depressed the pedal at traffic lights (one a Plymouth (80K) the other a Porsche (55K) - I'll let you decide whether or not the clutches were bad designs or poor construction).

FWIW #2:

When I changed the Plymouth clutch I took the advice of the parts counter guy and changed only the clutch diaphragm because he said the pressure plate and throw-out looked fine (really badddd advice).  The "repair" lasted all of ONE clutch pedal depression/clutch engagement.  Had to drop the tranny a second time and put in a new pressure plate and throw out bearing.  For the rest of my life IF I have to put in a clutch, the car will get the full package!!