The Clutch Prob Post
04-02-2004, 06:58 PM
#1
11 Second Club
Thread Starter
The Clutch Prob Post hey mods this is my clutch write up.
if you think it is sticky worthy please make it one....
in the first part of this we will review how your basic hydrolicly assisted
clutch works, then we will answer some VERY comman clutch system woes that
plague the ls1 community.
the flywheel
is connected to the engine,
and the clutch plate
is connected to the transmission
When your foot is off the pedal,
the springs push the pressure plate
against the clutch disc,
which in turn presses against the flywheel.
This locks the engine to the transmission input shaft,
causing them to spin at the same speed.
The amount of force the clutch can hold depends on the friction
between the clutch plate and the flywheel,
and how much force the spring puts on the pressure plate
When the clutch pedal is pressed,
it engadges your master clyinder
which draws fluid from your
clutch fluid resivour and pushes it via the hydrolic line to your
slave cylinder which engadges a
hydraulic piston that pushes on the release fork,
which presses the throw-out bearing against the middle of the diaphragm spring.
As the middle of the diaphragm spring is pushed in,
a series of pins near the outside of the spring causes the spring to pull
the pressure plate away from the clutch disc (see below).
This releases the clutch from the spinning engine.
(clutch plate)
Note the springs in the clutch plate.
These springs help to isolate the transmission from the shock
of the clutch engaging.
COMMON PROBLEMS
i have not upgraded my clutch or my supporting componaints. the clutch smells
very bad and there is a noticable slip.(a quik way to check if your clutch is
slipping is to place it in 6th gear at about 2000 rpms and floor it, if your
rmps rise quicker then your car accelerates then it is in fact slipping)
why?
The most common problem with clutches is that the friction material
on the disc wears out. The friction material on a clutch disc is very
similar to the friction material on the pads of a disc brake,
or the shoes of a drum brake -- after a while, it wears away.
When most or all of the friction material is gone,
the clutch will start to slip,
and eventually it won't transmit any power from the engine to the wheels.
The clutch only wears while the clutch disc and the flywheel are spinning
at different speeds. When they are locked together,
the friction material is held tightly against the flywheel,
and they spin in sync. It is only when the clutch disc is slipping against
the flywheel that wearing occurs. So if you are the type of driver who slips
the clutch a lot, you will wear out your clutch a lot faster. if your clutch
is slipping this much then it is time for a new clutch disk and flywheel ,
it is at this time that most people choos to upgrade their whole clutch
system(a good idea)
my clutch will not engage at all,i push the clutch pedal in but it will not
go into gear why?
there are a few reasons for this. most often you have a bad throwout bearing
or related clutch assembly part, for this particullar trouble it is time to
replace you clutch assembly and it is a good idea to either replace your
flywheel or have it resurfaced at this time as it will not cost you more to
have these parts put in at the same time.
under normal driving my clutch works fine,but at wide open throttle my clutch
sticks to the floor in 3rd gear and i can not get it to shift into 4th...why?
this one is very common with ls1 fbodys. you do not have a fried clutch. the
problem 90% of the time happenes after you got you car tuned and or raised
your rpm limiter. gm put a restriction in the hydrolic line inbetween the
master cylinder and the slave. this restiction lets only a measured amount of
clutch fuid flow from one to the other, it was placed the to make shifts more
smooth feeling and give the pedel a softer feel. the sotultion to this line
restriction is a simple procedure refered to as the drill mod. in short it
is removing the line, using a drill to bore out the restiction and replacing it.
for instruction on doing this yourself you can find it on
www.installuniversity.com
under normal driving my clutch feels soft but works fine, under wide open
throttle there is many times i can not get the car to shift at any given
gear until the rpm's come down. i have already done the drill mod(or not). what
could it be ?
the answer to this one is an easy one however the reason that it exhists is
not. this symptom almost always points to air in your hydrolic lines.
the reason it causes this problem is because, unlike the clutch fluid that
is supposed to occupy that space, the air that now resides there can be easily
compessed. this creates that "sqishy" feeling you can get in your pedel.
also the fact that it compresses means that the fluid is not pushing the
pressure plate to its full disengaged state, under wide open thottle where
it requires even more pressure to fully disengage the pressure plate, the
compression of said air is often time enough to not allow the pressure plate to
disengage at all, making it nearly impossable to get into the next gear up.
the fix is an easy one. bleed down your clutch hydrolics very carefully until
all the air bubbles have been removed. there is a write up on how to do this on
www.installuniversity.com
or you can goto any shop and have it done for a very nominal fee.
now the bad news.if you never have this problem again(lets say after 3 months)
then you are fine and the air probably got there when you performed the drill
mod. however if you have either not done the drill mod or the sypmtom returns
then you have a bigger problem. there is a leak ing your hydrolic system.
the first culprit to look at is your master / slave line.. inspect it for
kinks or pin holes. next is your slave. if you have gone through the trouble
to remove it go ahead and replace it.
i just replaced my worn out clutch with a brand new clutch. the clutch grabs
strong and does not slip at all. but the clutch disengagement happens only
1-2 inches from the floor board and in wide open thottle at higher rpms it will
not shift into the next gears....why?
several times people replace their tired clutch with the latest /greatest clutch
but forget to upgrade the supporting pieces. because the brand new clutch and
flywheel that you just installed have MUCH more material then your old worn
out peice. it takes more pressure to completely disengage the clutch disc from
the new flywheel. the first step is to do the drill mod discussed before. if
that does not cure your trouble then it means that your clutch requires much more
fluid pressure in order to opperate propperly. your stock master even after the
drill mod can only push a very set amount of fluid. if this set amount is not
enough to push the pressure plate then it is time to step up to an adjustable
master cylinder. this will allow you to increase the fluid pressure enough to
opperate your new clutch. it will also allow you to adjust exactly where in
your pedel traval your clutch engages and disengages.
there is one company that attemps a more simplistic fix known as a slave shim.
this effectivly shortens the space that the fuid resides in therefore putting
a "preload" on your fluid pressure. 2 reasons i dont like this quik fix.
1. it is not adjustable making it impossable to correct your pressure settings
as your clutch pad and flywheel wears making it nessissary to replace both
of them sooner then you would have to if you could adjust the correct amount
of pressure.
2. also because it is not adjustable it does not account for those whos master
puts out a little more then it was built to. for these people they will
notice that their clutch engages and disengages in the very first 1-2 inches
of clutch pedel travel. if this is the case there is a very good chance that
your clutch is never truely fully engaging, the result is a broken or worn
out clutch disk very early in the new clutches life, and a very displeased
customer who thinks this part was junk. it was not the clutches fault at all,
rather it is all in the supporting hydrolics.
in closing what can be gained from this is that the mass majority of troubles
that people have with their clutches are not really the clutches fault at all.
most of the time the trouble lies in the supporting components. many people will
say that when they replaced their clutch that it fixed a trouble simular to
yours, however if they took a step back and looked they would see that a few good
clutch manufactorers intrstruct you to upgrade peices mentioned before. THAT and
not the clutch may have been what fixed thier problem. so word to the wise.
check the simple less expencive supporting components before you drop 500-1200
on that new clutch.....
hope this helps
if you think it is sticky worthy please make it one....
in the first part of this we will review how your basic hydrolicly assisted
clutch works, then we will answer some VERY comman clutch system woes that
plague the ls1 community.
the flywheel
is connected to the engine,
and the clutch plate
is connected to the transmission
When your foot is off the pedal,
the springs push the pressure plate
against the clutch disc,
which in turn presses against the flywheel.
This locks the engine to the transmission input shaft,
causing them to spin at the same speed.
The amount of force the clutch can hold depends on the friction
between the clutch plate and the flywheel,
and how much force the spring puts on the pressure plate
When the clutch pedal is pressed,
it engadges your master clyinder
which draws fluid from your
clutch fluid resivour and pushes it via the hydrolic line to your
slave cylinder which engadges a
hydraulic piston that pushes on the release fork,
which presses the throw-out bearing against the middle of the diaphragm spring.
As the middle of the diaphragm spring is pushed in,
a series of pins near the outside of the spring causes the spring to pull
the pressure plate away from the clutch disc (see below).
This releases the clutch from the spinning engine.
(clutch plate)
Note the springs in the clutch plate.
These springs help to isolate the transmission from the shock
of the clutch engaging.
COMMON PROBLEMS
i have not upgraded my clutch or my supporting componaints. the clutch smells
very bad and there is a noticable slip.(a quik way to check if your clutch is
slipping is to place it in 6th gear at about 2000 rpms and floor it, if your
rmps rise quicker then your car accelerates then it is in fact slipping)
why?
The most common problem with clutches is that the friction material
on the disc wears out. The friction material on a clutch disc is very
similar to the friction material on the pads of a disc brake,
or the shoes of a drum brake -- after a while, it wears away.
When most or all of the friction material is gone,
the clutch will start to slip,
and eventually it won't transmit any power from the engine to the wheels.
The clutch only wears while the clutch disc and the flywheel are spinning
at different speeds. When they are locked together,
the friction material is held tightly against the flywheel,
and they spin in sync. It is only when the clutch disc is slipping against
the flywheel that wearing occurs. So if you are the type of driver who slips
the clutch a lot, you will wear out your clutch a lot faster. if your clutch
is slipping this much then it is time for a new clutch disk and flywheel ,
it is at this time that most people choos to upgrade their whole clutch
system(a good idea)
my clutch will not engage at all,i push the clutch pedal in but it will not
go into gear why?
there are a few reasons for this. most often you have a bad throwout bearing
or related clutch assembly part, for this particullar trouble it is time to
replace you clutch assembly and it is a good idea to either replace your
flywheel or have it resurfaced at this time as it will not cost you more to
have these parts put in at the same time.
under normal driving my clutch works fine,but at wide open throttle my clutch
sticks to the floor in 3rd gear and i can not get it to shift into 4th...why?
this one is very common with ls1 fbodys. you do not have a fried clutch. the
problem 90% of the time happenes after you got you car tuned and or raised
your rpm limiter. gm put a restriction in the hydrolic line inbetween the
master cylinder and the slave. this restiction lets only a measured amount of
clutch fuid flow from one to the other, it was placed the to make shifts more
smooth feeling and give the pedel a softer feel. the sotultion to this line
restriction is a simple procedure refered to as the drill mod. in short it
is removing the line, using a drill to bore out the restiction and replacing it.
for instruction on doing this yourself you can find it on
www.installuniversity.com
under normal driving my clutch feels soft but works fine, under wide open
throttle there is many times i can not get the car to shift at any given
gear until the rpm's come down. i have already done the drill mod(or not). what
could it be ?
the answer to this one is an easy one however the reason that it exhists is
not. this symptom almost always points to air in your hydrolic lines.
the reason it causes this problem is because, unlike the clutch fluid that
is supposed to occupy that space, the air that now resides there can be easily
compessed. this creates that "sqishy" feeling you can get in your pedel.
also the fact that it compresses means that the fluid is not pushing the
pressure plate to its full disengaged state, under wide open thottle where
it requires even more pressure to fully disengage the pressure plate, the
compression of said air is often time enough to not allow the pressure plate to
disengage at all, making it nearly impossable to get into the next gear up.
the fix is an easy one. bleed down your clutch hydrolics very carefully until
all the air bubbles have been removed. there is a write up on how to do this on
www.installuniversity.com
or you can goto any shop and have it done for a very nominal fee.
now the bad news.if you never have this problem again(lets say after 3 months)
then you are fine and the air probably got there when you performed the drill
mod. however if you have either not done the drill mod or the sypmtom returns
then you have a bigger problem. there is a leak ing your hydrolic system.
the first culprit to look at is your master / slave line.. inspect it for
kinks or pin holes. next is your slave. if you have gone through the trouble
to remove it go ahead and replace it.
i just replaced my worn out clutch with a brand new clutch. the clutch grabs
strong and does not slip at all. but the clutch disengagement happens only
1-2 inches from the floor board and in wide open thottle at higher rpms it will
not shift into the next gears....why?
several times people replace their tired clutch with the latest /greatest clutch
but forget to upgrade the supporting pieces. because the brand new clutch and
flywheel that you just installed have MUCH more material then your old worn
out peice. it takes more pressure to completely disengage the clutch disc from
the new flywheel. the first step is to do the drill mod discussed before. if
that does not cure your trouble then it means that your clutch requires much more
fluid pressure in order to opperate propperly. your stock master even after the
drill mod can only push a very set amount of fluid. if this set amount is not
enough to push the pressure plate then it is time to step up to an adjustable
master cylinder. this will allow you to increase the fluid pressure enough to
opperate your new clutch. it will also allow you to adjust exactly where in
your pedel traval your clutch engages and disengages.
there is one company that attemps a more simplistic fix known as a slave shim.
this effectivly shortens the space that the fuid resides in therefore putting
a "preload" on your fluid pressure. 2 reasons i dont like this quik fix.
1. it is not adjustable making it impossable to correct your pressure settings
as your clutch pad and flywheel wears making it nessissary to replace both
of them sooner then you would have to if you could adjust the correct amount
of pressure.
2. also because it is not adjustable it does not account for those whos master
puts out a little more then it was built to. for these people they will
notice that their clutch engages and disengages in the very first 1-2 inches
of clutch pedel travel. if this is the case there is a very good chance that
your clutch is never truely fully engaging, the result is a broken or worn
out clutch disk very early in the new clutches life, and a very displeased
customer who thinks this part was junk. it was not the clutches fault at all,
rather it is all in the supporting hydrolics.
in closing what can be gained from this is that the mass majority of troubles
that people have with their clutches are not really the clutches fault at all.
most of the time the trouble lies in the supporting components. many people will
say that when they replaced their clutch that it fixed a trouble simular to
yours, however if they took a step back and looked they would see that a few good
clutch manufactorers intrstruct you to upgrade peices mentioned before. THAT and
not the clutch may have been what fixed thier problem. so word to the wise.
check the simple less expencive supporting components before you drop 500-1200
on that new clutch.....
hope this helps
Last edited by jaberwaki; 08-21-2005 at 07:04 PM.
04-02-2004, 07:57 PM
#4
11 Second Club
Thread Starter
from z28hookie
May want to mention that for a daily driven or frequently driven car- Steel flywheels are a safer/more durable choice (for the same reasons you dont use aluminum connecting rods). I dunno- a lot of people see them as cheap horsepower (since they are replacing the flywheel anyway) and have NO idea that it is more susceptable to deformation from deflection and has a finite fatigue life...whereas steel is more forgiving... I'm sure more than 1 person has learned this the hard way...
May want to mention that for a daily driven or frequently driven car- Steel flywheels are a safer/more durable choice (for the same reasons you dont use aluminum connecting rods). I dunno- a lot of people see them as cheap horsepower (since they are replacing the flywheel anyway) and have NO idea that it is more susceptable to deformation from deflection and has a finite fatigue life...whereas steel is more forgiving... I'm sure more than 1 person has learned this the hard way...
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04-02-2004, 11:38 PM
#8
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Join Date: Apr 2004
Location: Ft. Myers, FL
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ok, at the risk of sounding like a dumb girl, I was lost. Could be that it's after midnight and I worked 8 am to midnight...could just be I read it kinda fast...
Maybe I'll try again tomorrow. I'm sure if I take the time to read carefully, I'd get it... Actually, guess I'll have to get it...i'm gonna change out the clutch with the next oil change. I'll let you know if this helped when I'm done!
Maybe I'll try again tomorrow. I'm sure if I take the time to read carefully, I'd get it... Actually, guess I'll have to get it...i'm gonna change out the clutch with the next oil change. I'll let you know if this helped when I'm done!
04-04-2004, 12:51 AM
#11
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Thanks, Very nice right up. This to me is worth bookmarking or stickying. I have a general knowledge of how clutches work, but I like how you highlighted the parts of what certain problems could be caused by.
I wuold aslo lkie to pinot out taht yuor sepllnig is fnie and taht msot poelpe can raed txet eevn if the leettrs are not in oredr.
I wuold aslo lkie to pinot out taht yuor sepllnig is fnie and taht msot poelpe can raed txet eevn if the leettrs are not in oredr.
