i have a new master and new slave, and rodneys adjustable banjo and still no luck, but i wonder if i could relocate the slave closer to the lever and make it work., i know how i would do it, but would it work is the question

no.
i'm sure someone else with more energy will explaine why.

but no. it wont do any good.

Buddycraigg is correct moving it will not help. The length of stroke the slave should be able to make is way more than you should need.

Maybe this information might help and you could try the bleeding method.

https://www.fiero.nl/forum/Forum2/HTML/082567.html

nope. wont change a thing. the slave will move exactly the same amount. and that amount is determined by the movement of the master.
if you are getting not enough slave action, there are few reasons: air in clutch line or bent clutch pedal. there is also the old upside down banjo fitting on the master pushrod.
if you want more clutch action from the existing system as it sits, all you can do is trying changing the "leverage" of the clutch arm - moving the pushrod closer to the center for more action, further from center for less action. but, this is probably just asking for trouble. the master & slave cyl are cheap (compared to getting a custom clutch arm made...)

...if you have air in the line (or as bent pedal), moving it closer with not help. The reason you are not getting enough throw is:

1) you are not getting throw from the pedal - Rodney's adjustable banjo would help some, but if the pedal is bent you will only be hiding the problem.

2) if you have air in the line, air compresses way more than the fluid does, so as you supply pressure, the air compresses and eats up any movement that you should get.

...it is also well documented that there have been many problems with new slaves not sealing properly...

Did you bench bleed the master before putting it on the car?

Try Dodgerunner's method, but I would suggest you park the car on a slope (passenger side down) to help eliminate air in the slave.

My method of bleeding (take 2 people), makes sure the master is full, press and hold the pedal, open the bleed screw, push the slave push rod into the cylinder, close bleed screw, release pedal, push pedal once, fill master, press pedal a few more times to seat the slave rod (always check and fill the master), repeat 3 or 4 times and you should be good.

Everyone is correct, you won't get more throw that way...

HOWEVER, if you have slop in your system because of a bent clutch pedal you might get a better clutch release by a longer rod on the slave cylinder.

In a perfect world that woudn't be necessary, but in a 20+ year old car sometimes you have to compensate with one part for another part that is worn out.

I would try changing the clutch pedal next since you have all new hydraulics and the adjustable banjo.

quote Originally posted by jscott1: HOWEVER, if you have slop in your system because of a bent clutch pedal you might get a better clutch release by a longer rod on the slave cylinder.

i think you mean longer banjo rod on the master.

When I replaced the old stamped steel clutch actuating lever arm for a forged unit on my Isuzu 4-speed, I had a problem in that the slave cylinder no longer provided enough "reach." I made a few rods of varying length that fit between the slave cylinder and the new clutch actuating arm. This was back in 1991, and has worked great ever since. I think I used 3/8" diameter round bar (might've been 5/16"), ground the ends round, and varied the lengths about 1/8" each. After test fitting a couple of 'em, the third one worked great.

quote Originally posted by buddycraigg: i think you mean longer banjo rod on the master.

No actually I meant a longer slave cylinder rod but a longer banjo rod might work too.

When I bought my 84 I noticed that someone had installed a socket on the end of the slave cylinder rod, effectively making it longer. I took it off only to discover I could no longer disengage the clutch.

I added an adjustable banjo and a new clutch pedal and I got good release with the stock slave cylinder length.

quote Originally posted by jscott1: No actually I meant a longer slave cylinder rod but a longer banjo rod might work too. When I bought my 84 I noticed that someone had installed a socket on the end of the slave cylinder rod, effectively making it longer. I took it off only to discover I could no longer disengage the clutch. I added an adjustable banjo and a new clutch pedal and I got good release with the stock slave cylinder length.

ugh...
would someone else explain it.
i dont have the energy

quote Originally posted by buddycraigg: ugh... would someone else explain it. i dont have the energy

No need to explain it I just did.

I don't know why people can't accept the fact that these 20 year old rickety clutches sometimes have to be modified from stock in order to work right. Yeah in a perfect world you don't need a longer slave cylinder, but if a longer one disengages the clutch then go for it. You won't get more throw, but you might get more "USABLE" throw where it's pushing on the clutch arm at a point where it will disengage.

[This message has been edited by jscott1 (edited 05-18-2007).]

Actually, a longer master rod might hurt more than help, if installed improperly. Especially if it is a new style master.
If the master piston does not return all the way on the new style, it won't open the port to the reserve which will cause issues.
on the old style a longer master rod will reduce the piston travel.
Now this is assuming that the longer rod does not allow the master piston to return to it's normal rest point, something that would need to be setup with the adjustable banjo carefully.
I wonder if some with the adjustable banjo who still have problems might have it set too long.....
That would then require a longer slave rod as there would be less travel, and you would need to take all excess play out with the slave rod.
But overall, the problems now are the result of poor design to begin with, there should have been more throw than needed designed in, not just the amount you need. 1/2 pedal should have been full disengage, not full.

Using a longer pushrod on the slave will simply push the piston deeper in the bore. It would be the same effect of moving the slave closer to the release arm.
Simply changing where the piston sits in the bore at rest.

The same amount of fluid is going to come from the master cylinder, so the piston in the slave is going to move the same distance. No matter where it’s starting point is.

There are three scenarios that a longer push rod could actually help with a clutch problem.

1. You use a pushrod so long that the piston bottoms out in the slave when the pedal is all the way up. So the clutch is already “preloaded” if you will, and keeping a bit of pressure on the release arm.
This might help if you are not getting much travel at the master, from a bent pedal or slop at the banjo eye.
I really don’t recommend this fix.

2. if you have an odd pressure plate or have done an engine swap and now the slave piston is hitting the snap ring at the end of the bore before the clutch is released. Or the clutch arm is bent and or rotated on shaft of the fork.

3. the most common problem.
Corrosion has developed in the outer 1/2 of the bore.
When the piston seal moves past this pitted area it takes in a little bit of air or leaks a small amount of fluid.
Using a longer pushrod would move the pistons starting point deeper in the bore so it’s stopping point will be deeper in the bore and possibly still within the “good” area.

So I agree that there are some examples of a longer rod covering up the real problem. But since dreyko has a new slave there shouldn’t be any pitting. A longer pushrod would do nothing in this case.

[This message has been edited by buddycraigg (edited 05-19-2007).]

how would you go about adding more throw to it then? could you swap in a different master cylinder so that you would get more than enough throw out of it? as it is, if you dont get it perfect, the clutch doesnt work right

larger master or smaller slave bores would do it.
or shorter release arm. if you move the point where the pushrod comes in contact with the arm closer to the shaft of the release fork the same 1 inch of movement will increase the degree of rotation of the shaft.

the second generation nissan 300z had such a large bore on the master cylinder it had it's own powerbooster much like the one used for the brakes.

These guys are correct on not being able to change the anount of displacement the master can make on a given stroke versus diameter. How about I throw everyone a curve ball.

My solution is not for "the bleed it again" folks. I am a hydraulic specialist by trade, this system is easy.
So...... My solution to this issue. Why not change the displacement of the slave cylinder?

I have changed to a V6 power plant coupled with my Isuzu 5 psd. Everything was fine but I just couldn't get the travel I wanted with the clutch. It ok, but just not enough for that smooooth shift I wanted. The only thing that was left out of the mix was the Adjustable banjo. I changed out the slave, master cyl, new pedal assembly, new cables, rebuilt shifter and bleed it until the pedal was rock hard with zero travel to get pedal movement. I decided that I needed more travel of the clutch, period. I elected to change the displacement of the slave cylinder as it is the only venture worth exploring. Off to my O-ring stash.

I picked up a few high pressure teflon back up rings (used in 3000psi+ systems) that are some what close in size to the smallest portion of the salve cylinder. They are split in half thus install is easy, they stay put and do not degrade in brake fluid. Win win... Ok, this will be where the cylinder is smallest and return spring attaches. I slipped about 4 or 5 teflon retainers over the cylinder to free float. All they do is take up space in the slave cylinder, nothing more. No magical sealing are induced or anything. These things take up space, ie; volume. It took a couple of trys to get what I was looking for. How much volume was changed? Very minimal. But the hydraulic clutch in our cars can be changed by resurfacing the flywheel a few thousanths of an inch. So by reducing the volume of the slave cylinder I have managed to increas the clutch disengagment potential a tad bit, if 1/32 of inch at all. Results, achievable and attainable victory. This does not mean jam some BS in there and hope it works. Think hydraulic and think TOW TRUCK, clutch, transmission and big money. This option is not for everyone and if you screw it up, hey its your transmission and engine. Everyone is thinking about the master cyliinder, I figure its set in stone right now until some junk yard bubba finds a gold mine in some other car that fits ours.

If any one has questions I'll answer them as best I can. If pics become available I'll post them.

88Ironduke

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Pilots with out maintainers are just pedestrians with a cool jacket and sunglasses.
I.Y.A.M.Y.A.S.

quote Originally posted by jscott1: I don't know why people can't accept the fact that these 20 year old rickety clutches sometimes have to be modified from stock in order to work right. Yeah in a perfect world you don't need a longer slave cylinder, but if a longer one disengages the clutch then go for it. You won't get more throw, but you might get more "USABLE" throw where it's pushing on the clutch arm at a point where it will disengage.

I've found time and time again that if all of the components of the clutch hydraulic system are stock AND in good condition - it'll work fine.

But there's not a lot of extra motion available, so minor problems can cause the system to fail to work correctly. A bent clutch pedal will reduce the amount of travel available - I've seen at least two steel clutch pedals that were bent. Those stamped steel clutch release arms are a problem, too. And the slave cylinder is a common trouble spot. If you bleed the system but the air comes right back, you've almost certainly got a bad slave cylinder.

Here's what I do when I need to fix a clutch hydraulic problem: first, check the clutch pedal (should stand about 1" higher than the brake pedal), make sure the banjo is straight, check the clutch arm to make sure it's got the cast iron arm. Check the master for leakage. Next, disconnect the clutch line at the master and slave ends; attach rubber tubing to the master end of the line and dip it into a gallon of denatured alcohol. Suck about half a gallon through the line with a vacuum pump / catch can - this will clear the line of the contaminated fluid, rust, and other debris.

If the master isn't leaking then flush it out using the rest of the denatured alcohol; catch can under the master outlet and pour it in, work the clutch pedal a couple of times to clear out the cylinder bore. Now blow out the lines and master with clean air, replace the slave cylinder and hook the lines up. Refill the system with DOT5 synthetic brake fluid, bleed it and you're done. It'll work perfectly after this procedure.

Moving the slave closer to the lever won't increase the travel of the clutch, but relocating the pivot pin on the clutch pedal will. I agree with previous posts that if everything is stock and in good condition this shouldn't be needed, but with high presure clutches and engine swaps it can be benificial to increase the travel of the slave to utilise it's full stroke. The pin in this pic is actually moved a bit more than needed to get all the available travel in the slave, but you get the idea. in this modification the master push rod is flipped over so the offset end is on the oposite side of the rod, thereby maintaining alignment of the rod into the master cyl.

the stock pedal is the one on the bottom in this pic.

[This message has been edited by Russ544 (edited 05-20-2007).]

I don't disagree with anything you all said. If you replace everything in the hydraulic system with good condition stock parts of course it will work. But if you need a band-aid to get the car moving off the side of the road, a longer slave might work. I said might, there are no guarantees.

quote Originally posted by 88Ironduke: If any one has questions I'll answer them as best I can. If pics become available I'll post them.

i would love for you to explain how adding a solid mass inside the slave cylinder bore is going to increase the amount of movement of the pistion.

What i have done is actually move the little plastic cup, that the slave cyl rod sits in, on the clutch fork arm. By moving the cup towards the pivot point of the clutch fork. I moved mine about a 1/8 inch or so and my clutch problems where no more. Mine was from a isuzu and was made from sheet metal rather than cast. This also increases the throw at the clutch fork.

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REMEMBER KIDS 4.9 ARE NOT SBC's

quote Originally posted by buddycraigg: i would love for you to explain how adding a solid mass inside the slave cylinder bore is going to increase the amount of movement of the pistion.

This is basic hydraulics, for a given stroke of the master a certain amount of fluid is forced into the slave cylinder... now if the slave cylinder is smaller that extra fluid has to go somewhere, in this case you get more stroke.

quote Originally posted by buddycraigg: i would love for you to explain how adding a solid mass inside the slave cylinder bore is going to increase the amount of movement of the pistion.

I'm with you Buddy, seems you would only be changing the static volume of fluid in the slave.
Yes it's basic hydraulics the master is only going to move a fixed volume of fluid.
The slave movement is going to be determined by the diameter of the piston and volume displacement by that fixed volume of fluid.

Another way of looking at it is anything you put in the slave is just displacing fluid out of the slave at rest.

He said it himself, a smaller cyl would give more movement. Since you have not changed the diameter of the cyl. you have not changed the stroke.

[This message has been edited by Dodgerunner (edited 05-21-2007).]

there is also the option of making a new clutch arm, with the cup closer to the pivot point - kinda like a short shifter.
of course, this may mean chaning the angle of the pushrod vs the clutch arm too.

quote Originally posted by Dodgerunner: I'm with you Buddy, seems you would only be changing the static volume of fluid in the slave. Yes it's basic hydraulics the master is only going to move a fixed volume of fluid. The slave movement is going to be determined by the diameter of the piston and volume displacement by that fixed volume of fluid. Another way of looking at it is anything you put in the slave is just displacing fluid out of the slave at rest. He said it himself, a smaller cyl would give more movement. Since you have not changed the diameter of the cyl. you have not changed the stroke.

Donning flame suit......

What I came up with not a position of static verusus dynamic volumetrics. Its hydraulics 101. The master cylinder must move a fixed amount of fluid. Imagine if the smallest portion of the slave cylinder piston was not machined like you see. Lets say the piston was a constant diameter and did not have the little area for the spring to attach to. The reduction in piston volume would cause a shorter stroke versus simply because there is more area for the fluid to fill, static or dynamic. Any change in the volume of the slave cylinder piston will result in stroke change. Have you wondered why GM machined the slave cylinder piston as they did? It is not a flat piston like one might expect. What is the need for the long piston tip to attach the return spring too? The narrow portion, and its length inside of the slave cylinder takes up space and creates part of the equation nesseccary to achieve a desired movement. Make that narrow portion of slave longer. The volume of the slave cylinder has been reduced even though piston diameter has not changed. A longer stroke is induced. If you doubt, take your trusty hacksaw and cut that little portion off the piston and see what the travel is. I can assure you it will be shorter than what you need for smooth shifting.

Simplified version, fill the bath tub up and climb in. Water lever inside the tub went up because you reduced the amount of space inside by climbing in. But you did not change the volume of water, just its displacement inside a fixed chamber.

Flame suit removed.

88Ironduke

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Pilots with out maintainers are just pedestrians with a cool jacket and sunglasses.
I.Y.A.M.Y.A.S.

i'll be back.
i have to calm down a bit

Please don't take this as flaming, it's just a friendly discussion.

The slim part of the pistion is to provide a point for the spring to attach as well as a stop limit for bottoming out in the cyl.

If I cut the slim part off the pistion it will not changing the dynamic volume of the cyl. only the static. When you bleed the slave the part you cut off would be replaced with fluid making up a volume equal to the volume of metal removed. That volume will just come from the master which would lower the level at the master. When the clutch is then used nothing would be different. The added amount of fluid would move just like the metal part would. I.E. it does not matter if what is in the slave cyl is fluid, metal, or rubber when at rest it's just volume. The only thing that matters is the amount of fluid that moves back and forth between the master and slave.

The static volume of the clutch system is a set enclosed volume (full system). Then at rest the slave will return to the same point (not accounting for wear) and the master will always return to the same point therfore the total volume of fluid in the system is a set amount.
The bathtub example is not correct because the tub is not a full enclosed system and the water only displaces air from the tub.

Using your tub example it has to be done this way.
Fill the tub part way and add a bowling ball and mark the water level. This is the starting point. Get in and again mark the level again.
Now start over and remove the bowling ball from the tub, But you have to return to the starting level so you have to add some water to bring it back to the same starting level as it was before. (just like the o-rings you added would displace fluid back to the master)
Now climb back in. Is the water level going to be any different than it was the last time you where in the tub?

[This message has been edited by Dodgerunner (edited 05-21-2007).]

im not going to get into this friendly discussion or flame war or whatever. im interested in the pic of the modified clutch pedal by russ 544. you moved the post down towards the foot thereby giving a little bit more throw and you only need a LITTLE bit more throw to have a lot more fluid pumped - by lowering the pivot post and turning the banjo over you gain. my spare clutch pedal gives me a measurement that the pivot of the banjo is 2 1/4" from the fulcrum of the clutch pedal. you can gain at least 1/2" by lowering the clutch pivot. so the ratio is 11/9. my 11" clutch pedal travels 6" at the foot. thats 1.23" at the clutch pivot. 11/9 of 1.23" is 1.5" - hey thats a full 1/4" more movement at the master cylinder. thats at least 1/4" more movement at the slave - a MAJOR improvement. why, ive got an extra clutch arm and i just might try this mod. thanks russ544, a simple solution to a complex problem - but for all of you with weak legs, you might find that it increases your effort by 11/9 or 22%.
much obliged
jon

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I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!

quote Originally posted by longjonsilver: im not going to get into this friendly discussion or flame war or whatever. im interested in the pic of the modified clutch pedal by russ 544. you moved the post down towards the foot thereby giving a little bit more throw and you only need a LITTLE bit more throw to have a lot more fluid pumped - by lowering the pivot post and turning the banjo over you gain. my spare clutch pedal gives me a measurement that the pivot of the banjo is 2 1/4" from the fulcrum of the clutch pedal. you can gain at least 1/2" by lowering the clutch pivot. so the ratio is 11/9. my 11" clutch pedal travels 6" at the foot. thats 1.23" at the clutch pivot. 11/9 of 1.23" is 1.5" - hey thats a full 1/4" more movement at the master cylinder. thats at least 1/4" more movement at the slave - a MAJOR improvement. why, ive got an extra clutch arm and i just might try this mod. thanks russ544, a simple solution to a complex problem - but for all of you with weak legs, you might find that it increases your effort by 11/9 or 22%. much obliged jon

jon,
May I make a suggestion, if you really feel that you need to modify the system.
When you lower the pivot point you will also need to slightly move it forward.
Otherwise the pedal will stop from the banjo holding it back rather than it actually hitting the rubber stopper built in to the pedal assembly

We now return you to the lively discussion on hydrostatics and fluid dynamics

PS, oops, i'm signed in under Polly's name

[This message has been edited by pollycraigg (edited 05-21-2007).]

quote Originally posted by 88Ironduke: Donning flame suit...... What I came up with not a position of static verusus dynamic volumetrics. Its hydraulics 101. Flame suit removed. 88Ironduke

No need for a flame suit because first of all you are correct, second, you have already done it and it worked, (one test is worth a thousand expert opinions) and lastly Archimedes figured this all out 2,200 years ago and people are still wanting to argue about it on the internet... sheesh.

you are right polly, i notice that russ did move the pivot of the clutch banjo forward a tad - of course i also have an adjustable clutch banjo so maybe the ? is mute - provided i lengthen the banjo rod with the adjustment mechanism. im interested in this question because i spent one whole summer bleeding my clutch and screwing with adjustments and finally in september i tried archies method - in my case the gravity method didnt work. archies method did with the following modification - i used a hockey stick to depress the clutch while i turned the slave bleeder screw - just try to get my wife to help bleed my clutch again! heh heh still i periodically have trouble shifting into reverse when the engine is cold - 1500 rpm - at 2300rpm forget about it - let it warm up more. may i post part of archism #7?

quote archie B) The bore size of the Master Cylinder and the Slave Cylinder is the same size. C) Through one full stroke of the clutch pedal the piston in the Master Cylinder moves 1.20" Maximum. D) Because of C) the maximum travel of the piston in the bore of the slave cylinder is 1.20" E) To properly operate the stock Fiero Clutch you need 1.15" of travel in the hydraulic system to properly engage and dis-engage the clutch. F) Because of E) any inefficiency in the operation of the total system, (I.E. leaks or bad pedal or banjo on upside down) will cause one or more of the symptoms listed in the start of this posting.

jon

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I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!

quote Originally posted by jscott1: No need for a flame suit because first of all you are correct, second, you have already done it and it worked, (one test is worth a thousand expert opinions) and lastly Archimedes figured this all out 2,200 years ago and people are still wanting to argue about it on the internet... sheesh.

placing an o-ring inside the fluid area of the slave cylinder will not increase the amount of travel of the slave piston.

What you need to do to make the stock system work is reduce length of the clutch fork arm . By making the distance from the clutchfork shaft to the actual slave rod cup shorter, you actually increase the throw at the clutch. This mod is really easy to do if you have the sheetmetal clutchfork arm. I have been under the dash screwing around with the pedals and it sucks. Mod the arm it's way easier and it's effective. Also you can replace the plastic bushing with metal you reduce the slop in the clutch pedal system. I found a metal sleeve that slipped tightly over the pin on the clutch pedal. then i opened up the banjo to fit tight over the outer diameter of the metal bushing. I'll try to get some pics of my setup. It's on my beater and it has been sitting for some time. It worked good up until the 2.8 gave up

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REMEMBER KIDS 4.9 ARE NOT SBC's

Thinking outside the box and a place were it's a PITA to get to, I had this problem on my V8/getrag. Try looking at the release fork and arm at the transmission. I noticed galling and score marks on the bell housing behind the cast iron release arm. Found a few problems, The arm was traveling too far and the retaining bolt was gouging the aluminum. The push rod dug a pretty deep hole in the arm (about .08 material left) The stroke of the slave was about 1/4" but you could push it back into the slave about 3/4"

The real problems was the release arms down by the throw out bearing had worn down, so the engaged position was off from the start. And the cast iron arm had a hole 1/8 deeper then when new. This combination sucked up my available travel.

To Fix, new arm and new shaft or go to the later hydrolic throw out bearing.

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yellow 88 GT, not stock
white 88 notchie, 4 banger

quote Originally posted by FIEROPHREK: What you need to do to make the stock system work is reduce length of the clutch fork arm . By making the distance from the clutchfork shaft to the actual slave rod cup shorter, you actually increase the throw at the clutch. This mod is really easy to do if you have the sheetmetal clutchfork arm. I have been under the dash screwing around with the pedals and it sucks.

either way should work in theory: more throw available at the master or less throw needed at the slave. its the ratio of whats available and whats needed that is important. with stock, according to archie you have 1.20 available and need 1.15 - hey thats a 96% efficient system! no wonder we have so many clutch problems! how many of us were A+ students ALL the time? if my above calculations are correct, then we have 1.45" throw available at the master and only need 1.15 at the slave then we have a system that will work at only 79% efficiency. hey thats a C+ guys, i bet a lot more of us were C+ students than A+ students, and i bet a lot more clutches would work correctly if less efficiency were needed. i have a cast and a sheetmetal clutch arm, i might try your solution as well.
thanx
jon

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I'm the original owner of a white ' 84 2M4 purchased Dec 10, 1983 from Pontiac. Always garaged, no rust, 4-wheel drifts are fun!