Removing transmission

Page 7 of 8  


pressure
Yeah, they did, but since it's info from a man that worked as a mechanic on them back then, you would question it.

master
in
Go on believing that, John, if you wish. I have experienced otherwise, but since you do not accept my word. . . .

already
I am not backpedaling. From the original poster's statement, I assumed the system was known to be defective. My stupid mistake. I forget that reality doesn't always exist here.

had
a
It did.

Well, gee, John . . . .we rented the truck for six weeks and the problem never came back. Now, since the bled out fluid had no foreign matter in it, just bubbles, the reservoir had no crap in it, I think it would safe to say the problem was the darned air in the system.
-- Budd Cochran
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. . <inline> ======== ======== snipped-for-privacy@qwest.net (Big Al) wrote in message:
So what keeps the throw out bearing from riding on the clutch fingers? I don't remember seeing a spring of any kind under there.
Al ========== ==========
Nothing.....
if the systems working correctly.
~:~ Marsh Monster
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. . <inline> ========= ========= snipped-for-privacy@SPAM.citlink.net (Budd Cochran) wrote in message:
<snip>
However, an improperly bled hydraulic clutch can, when the system gets warm from under the hood heat, hold pressure on a throwout bearing . . .just like it would be if you rode the pedal.
--
Budd Cochran
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
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Try reading what Budd said. He mentioned nothing about the clutch. Simply said that an improperly bled system could result in faster than normal throwout bearing wear. That is not only possible, its probable.
--
Max

Give a man a match, and he is warm for a short while. Light him on fire, and
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I am not sure that this is exactly what Budd either said or meant but if YOU actually believe this Max, prove it because in reality, you are dead wrong. There is no way in hell that an improperly bled system could cause excessive wear to the bearing but it is highly probable to cause excessive wear to the clutch. I don't claim to be a hydraulics expert but there are some simple facts that seem to be completely distorted.
First of all, gas, liquid and solids ALL expand to some degree when heated with the difference being that liquids and solids apply EXTREME pressure when any expansion occurs and gasses do not unless the expansion is significant. The reason why there is a slight gap required in a mechanical clutch linkage is due to the possible expansion of the mechanical parts partially engaging the clutch and causing excessive wear and slippage to the clutch, not the bearing. The return spring serves to stop the linkage from rattling when in full release due to the required gap as much as anything else.
As for gravity, the weight of the fluid is so insignificant in a 3/16 line that I doubt that it could supply enough force to even move the clutch slave cylinder at all, never mind move it with enough force to cause excessive wear on the bearing.
Air in the system will also not cause the slave cylinder to move because if it expands, all it will do is push the fluid back into the master cylinder reservoir as at full release, the ports between the master cylinder and the reservoir are open, pretty much just like the brake master cylinder. It does however, have the ability to cause excessive clutch wear because it could prevent the clutch slave cylinder from moving enough to fully disengage the clutch when required due to its compressibility.
As for the bearing wear, I would think that it goes through as much wear sitting at a single traffic light while holding the clutch in as it does with a year of wear with the light to non-existent pressure being placed on it during normal driving when the clutch is fully engaged. It sounds like the OP simply has a bad bearing, possibly contaminated with dirt during assembly causing excessive wear and premature failure.
--
If at first you don't succeed, you're not cut out for skydiving



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If you have to ask this type of question, it is out of your league. Hire a pro!!
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Simply
YOU
wrong.
excessive
the
No, Tom, it depends on the VOLUME of air left in the system. On hydraulic machinery in the muffler factory, I've seen a 3" dia by 24" cylinder full of hot air bend a 3" exhaust pipe with a laminated wall 0.072" thick . . . .the heat coming from an oil based fire below the cylinder. Yeah, the set-up man lost his position because of poor housekeeping.
Then don't forget that all the power your engines make comes from coffee can sized volumes of air heated by burning fuel.

mechanical
the
from
And that's why there needs to be a gap on the hydraulic system,

slave
if
the
on
Now that could be a possibility.
-- Budd Cochran
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simple
of
.the
I think that you are comparing two different systems. The cylinder that you are talking about was in a closed system which gave the building pressure no where to go so it pushed the piston out with enough force to bend the pipe. In a hydraulic clutch, when the pedal is fully released, it is effectively an open system and any expansion of either gas or fluid will simply dump the excess into the reservoir without building any pressure by design.

And if the fire was as unintentional as you make it sound, he should have.

can
While true, you are dealing with both combustion and a closed system, neither of which exist in a hydraulic clutch at rest.

heated
anything
If the hydraulic clutch master cylinder is functioning properly, no gap will be needed as any change due to expansion or contraction should be dealt with by pushing excess fluid or pulling required fluid from the reservoir in the open at rest system.

line
cylinder
like
I would think the most likely one but then again, not the only one. The OP also didn't mention if he drives with his foot on the clutch pedal which would as you indicated, also cause excessive wear of the TO bearing.
--
If at first you don't succeed, you're not cut out for skydiving



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normal
if
to
hydraulic
full
you
no
pipe.
the
On the Pines bender in the example, the pistons have orifices to allow the wing die to follow the bending action. Pressure from the pump is applied to both sides of the piston with the extend line having up 30% higher flow to maintain contact with the pipe. In this example, the cylinder had been just rebuilt and was being installed. The millwright left the job for lunch and someone tossed a cigarette butt in the oily mess on the floor below the cylinder. The cylinder was connected, but no oil had flowed yet in a systems test.
I was the apprentice millwright on the job that day. When we heard the fire alarm, we went to help put it out and that's when I saw the bent pipe. The opposing wing die had not moved even though it is in parallel in the hydraulic circuit.

He had been told repeatedly to clean up the mess of oil absorbent (Petro-sorb) and dirt that he had tossed under the cylinder to catch the drips from the worn shaft seals. Another employee walked by and tossed a butt in the mess.

It can.

pressure
parts
to
will
with
the
Not in all systems.

excessive
because
and
It
it
wear
does
placed
during
OP
Ah, but would he admit it? I've caught many a forklift driver doing just that but had them refuse to admit it.
Budd
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but
wear
.
pressure
effectively
to
just
systems
I figured that the cylinder had to be empty or near empty to build up that much pressure and like I thought, the system was closed allowing the pressure to build up.

fire
Not seeing the system, I cannot make any valid comment on why it didn't move.

have.
Well, in all honesty, the idiot that threw the butt should have also been canned.

coffee
LOL, while the vehicle could catch on fire (the combustion part), no vehicles hydraulic clutch that I am aware of would be in a closed mode at rest and I know that the Dodge is not (since I have one) so at least in this case, and since the OP did not complain about hard shifting (a symptom of air in the system), air in the lines was probably not the cause here.

slippage
linkage
Possibly not but in automotive systems this will be the case. If you know of a production automotive system that is different, please let me know.

3/16
clutch
because
sounds
LOL, most people would not and some don't even realize that they are doing it.
--
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clutch.
dead
some
.
that
dump
the
to
and
Tom, if equal pressure is applied on both sides of a piston, which way does it move?
Now, again, there are flow controls in the circuit, the front and rear of the piston are interconnected and the fire would have heated the retract side of the piston first.
Come on, why did it do what it did?

The
But you have anyway.

In today's environment, probably. That factory is now a non-smoking establishment, even though the air is cloudy with oil smoke. Back then it wasn't and the worst he could have been charged with was negligence with the butt. The real problem was the oily mess.

this
Tom, are you going to start this kind of stuff again? I supposed now you are the expert in all hydraulics system malfunctions as well . . . .

when
is
gap
dealt
in
Ok, How about forklift systems ( sorry, but technically, they are still "automotive " systems), heavy truck, or our old 56 Plymouth wagon that had an optional hydraulic operated clutch. It adjusted the same as mechanical linkage, had a freeplay clearance of about 3/4".

cylinder
cylinder.
fully
much
it
The
which
Really? I used to and I knew it, and I corrected myself.
Budd
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applied
flow
the
that
does
It doesn't but who said that the pressure was equal? The key word here Budd is PRESSURE, something that WILL NOT happen in an open system.

If you say so, I wasn't there. As for being interconnected, I bet that there is a valve between the sides and that it was closed.

Like I said before, due to a pressure build up, something that does not happen in the modern open at rest hydraulic clutch of the OP's vehicle.

Not really, I just brought out the point that the pipe bender and hydraulic clutch are two very different systems, something that you refuse to realise.

the
a
been
the
Negligence is all that is needed to get people injured or killed and that oily mess was also really nothing more than negligence when you think about it.

at
of
are
LOL, I never claimed to be an expert in all hydraulic systems or all malfunctions with them but I do understand this type of system. As for me starting anything, not at all. You are simply wrong here and I am not the only one saying it and I am not bashing you for it, those days are done. While you may have significant experience in closed hydraulic systems, this is not a closed system at rest and many of the symptoms that you have experienced with them simply do not apply here. The address supplied by Marsh Monster Http://www.babcox.com/editorial/bf/bf70238.htm clearly describes the common hydraulic clutch system used in modern vehicles and as long as the system is open (any time it is at rest), no pressure can build up due to expansion.

know
Now you are just being silly. We are talking about a modern light truck, not a relic, heavy truck, or a damn fork lift and if you think that all four of these things use exactly the same hydraulic systems.... As for forklift systems being technically automotive systems, that is simply ridicules so that didn't answer the question at all and BTW, I asked for a specific system (specific vehicle), not a general class and make it a modern system (vehicle) as we are dealing with a modern vehicle in this thread.

just
doing
I can only speak for myself and sometimes when I have been stuck in slow moving traffic for a while and then it opens up, I sometimes forget that my foot is still on the clutch pedal. I usually realize it when I set the cruise.
--
If at first you don't succeed, you're not cut out for skydiving



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allow
been
lunch
Budd
But it's not an open system.

of
Nope. The hydraulic pump applied pressure to the wing cylinders equally WHEN IT WAS RUNNING. The fire happened while it was being changed over to bend a different size / type of exhaust pipe.
The pump pressure line teed to each wing but the rest of the system from the tee was still filled with hydraulic oil, just the one cylinder was empty.
Btw, bleeding that system is a ten minute job . . .ten minutes of bending cycles without pipe.

Tom, why is it important to bleed the air from a braking system? If you don't know all the reasons, then you don't know hydraulic clutch systems.

the
pipe.
didn't
hydraulic
realize.
And you forget the basics of hydraulic systems and that any hydraulic system can have the same troubles as any other.

should
tossed
it
about
Well, I'll excuse that as you didn't know the lazy character that had the job.

in
As do I and I've the experience of fixing those malfunctions.

Right . . . .

Unfortunately, you both are wrong is saying I'm wrong.

this
vehicles
can
Sorry, but it's not an open system. Sure, there's a small relief orifice, which has been used even in the earliest designs, for fluid replacement, but it's not an open system.

know.
had
mechanical
Nope, not at all. It's still an automotive vehicle and has similar systems. Tell us how the brake system differs, the engine operation, the transmissions ( auto and manual) the differential, the steering ( ok, it's a modified Ackerman design to allow tighter turns).
The only difference is possibly in the fuel used (propane for some) and the hydraulics pump . .which can be found on a dump bed conversion for a pick up truck.
Now, did you know that motorcycles, scooters, why even mopeds and those darn little electric scooters are "automobiles"?

four
And if you don't think they don't . . . .

Uh, oh, Tom's going to blow.
Tom, before you do, it's been 30 some years since I dove under a forklift floorboard and I don't remember brand / model / serial numbers for the exact forklifts I repaired, but the big Yale rental comes to mind because I had to fix it because the rental company's mechanic couldn't.
How did I learn how to fix it? When the other forklift mechanic, on first shift, the guy with the wallpaper (diploma), couldn't get one system bled out right, he still sent the truck back out for use. When I came in a few hours later, the clutch was smoking on it from trapped air. Now how do I know it wasn't a driver riding the clutch? That year of forklift could be started in gear (1962 Yale 4000 cap) and the driver had a cast on his left foot from having a horse step on it. He would shut the engine off to change direction or use his right foot to work the clutch for inching. Now why was he working with a broken foot? You would have had to work for that employer to understand.

my
I just remembered how my mom taught me to avoid it . . I tuck the clutch foot back under my right leg until I see I might need it again. In traffic, I keep it on the floorboard below the pedal.

Budd
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My wife still reminds me that I sometimes stomp my left foot on the floor after each shift. I don't even realize when I do it. When learning to drive, dad insisted that I stomp my clutch foot on the floor so he could hear it. By doing that he didn't have to constantly watch my feet to see if I was riding the clutch. 25 years later, I'm still stomping on the floor.
--
Ken



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Whatever works, right?
Btw, I used that stomping technique to train National Guard dump truck drivers, most of whom never drove a manual trans before signing up.
Now, as I understand it, most of the trucks are automatics . . . . -- Budd Cochran

drive,
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below
a
up
Yes it is, at rest. The diagram in the link provided clearly demonstrates that it is, regardless of your beliefs.

retract
WHEN
a
the
Since I was not there and have no schematic of the plumbing of this system, there is no point arguing about it and the fact that it is a very different type of system in every way, makes what happened to it a non-issue.

LOL, complete BS.

the
system
Once again, you are incorrect. While the basics of how they work may be the same, the problems that each type can have and how they effect the system can be very different. This is basic stuff here Budd.

mode
symptom
here.
you
Really? Which modern vehicles (CARS) did you make these repairs on?

I guess that when you say both, you are really reffering to John, Marsh Monster, Max, and myself.

but
Even going by your wording, what exactly do you think that "relief" means. You are just contradicting yourself here.

you
still
systems.
So does the space shuttle, is it an automotive vehicle as well? Having a few similar systems does not make it the same thing.

Some still have mechanical brakes, other only brake on the drive wheels. What cars still use these systems?

Many are fully electric and have been for ever. How many production vehicles fall into this catagory?

Many of the above electrics don't have shifting transmissions so again, how many cars fall into these catagories.

Most fork lifts stear from the rear wheeles, how many cars do that?????

the
up
Really, I looked all over my conventional pick up truck and for the life of me, I can't find that damn pump. I did find one for the steering and it does't seem to have a big problem with a little air in the system.

darn
While true here if you streach the definition, that is nt the case with a fork lift as it is not a road vehicle and is not designed to carry passengers.

I know that they don't.

so
system
exact
to
Nobody is doubting your skills as a fork lift mechanic but we are not talking about fork lifts or even 30+ year old vehicles.

change
was
employer
Since I was not there, I will not argue the point with you but what it had over 40 years ago is probably not the same thing that a modern passenger vehicle has so unless you can prove that it is, using it as an example is invalid. As for the employer, he would probably lose his business if he pulled stupid shit like that in today's world of lawsuits.

doing
traffic,
I started off with an automatic (65 Dodge Dart GT) and taught myself how to drive a standard shift (62 Falcon). My father did tell me to keep my foot on the floor under the clutch pedal when not shifting and for the most part, that is exactly what I do and anymore, I tend to shift it without the clutch at all. The problem is that it is not always practical and quite tiring to do that in the heavy traffic I would have to deal with in the GS parkway and when the traffic does finally ease up....
--
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Interesting that you have far more to say than is necessary, so some will be snipped, like it or not.

An improperly bled system has air in it. Air (any gas, be it air, or fluid vapor) can expand and contract due to temperature, and thus can allpy a small amount of pressure over designed pressure to the throwout bearing. In addition, vapor will cause inadequate release of the clutch, and thus the bearing will see much more use as the operator pumps up the system. Over time, this will cause a higher wear rate. Thats a fact, and its all common sense. If it wasn't true, there would be no reason to properly bleed the clutch hydraulics.

Clutch wear can only be caused by the TO bearing being shoved against the fingewrs of hte pressure plate. If you are going to claim that the clutch will wear faster (and it will, no doubt) then the TO bearing will ALSO wear faster. You seem to forget that for the clutch to slip, it needs something trying to disengage it, such as the TO bearing.

Jeez, I think I said that already, try reading.

This assumes the air/vapor is in the line, not the slave cylinder.

Rubbish. If the vapor is in the line and heads up to the master cylinder, it will have nothing to do with the slave cylinder position. Your facts are correct about air/vapor in the line, but if that is the only place air/vapor is, as you imply, it'll do nothing to the slave cylinder. You are again giving conflicting info and tripping yourself as you go. Typical.

You would think this, but you have no proof. Nor do I have proof otherwise. You are speculating, nothing more. We were simply listing reasons why a TO bearing might wear excessively. It could be that the TO bearing was flawed from the factory. Who knows.
Oh yeah, I bet YOU do..... do tell.
--
Max

Give a man a match, and he is warm for a short while. Light him on fire, and
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be
And edited to suit your needs again I see, LOL.

Duh, no shit. Thanks for pointing this out.

W R O N G ! ! ! In order for the "expanding gas" to build any pressure at all, it has to be in a CLOSED system and when the clutch pedal is fully released, the system is WIDE OPEN" Any expansion in the gas will do nothing more than push fluid into the reservoir and a contraction will pull a little out. Either was, NO measurable change in applied pressure to the bearing.

the
LOL, as you say, that depends on where the gas is. If it is in the slave cylinder or in the line close to it, all the pumping in the world will have little effect unless you can pump it really fast. So fast in fact that the slave never fully returns to its rest position and in that case, the additional wear is minimal.

common
Maybe in your world but for the rest of us in reality, it is pure BS.

Hahahaha, you are joking, right?!?!?

simple
wear
But is actuality, if the pressure plate is not being moved far enough to fully release the clutch disk, then the pressure being exerted by the TO bearing will actually be LESS than it would if the system were operating properly which would also cause LESS wear, not more on the TO bearing. Now if you think that air in the line will actually cause the clutch to slip under full engagement and cause excess wear to the bearing, that you really are an idiot.

line
cylinder
LOL, it does no such thing. It doesn't matter if the air is in the line or slave cylinder itself, the same thing will happen and if you don't think so, then you had better crack a few books.

Yes, most of what you are saying is just that, rubbish.

air/vapor
Like I said, PURE RUBBISH. Once the master cylinder begins to move, It doesn't matter where the vapor is because it then becomes a closed system and at that point, the gas will begin to compress and reduce the amount of travel of the slave cylinder depending on the amount of gas trapped in the system. Now if you soemhow think that the effect will be different depending on where the vapor is, please explain, I could use the laugh.

like
otherwise.
What's the matter Maxi, did I upset you again? I don't need proof of this as I suggested that was the probable cause. If it was a failure by design as you suggest, it would be happening to most if not all of them and I don't recall seeing many if any other posts describing this problem and my TO bearing has gone over 100,000 miles so far. The problem is that all of your suggestions are incorrect and many of them would have other symptoms such as "pumping up the system" that the OP never made any claim to having.
--
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Again, you talk too much, and snips will be made for brevity.

This assumes a properly working system. If it has an air bubble in it, its not working properly. The scenario you suggest implies that the system will bleed itself over time, which is simply not true in all cases.

Except for the extended period of time for clutch release. which would add to bearing wear.

Wrong, particularly in the case of a diaphragm pressure plate, where the load is higher at the beginning of clutch release than it is after full release. BTW, most clutches now days are the diaphragm design.

Never said it would cause the clutch to slip under full engagement, and specifically noted that it wouldn't.
Yet another attempt on your part to redirect attention from your erroneous BS.
--
Max

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