88 GT 5-speed with 50k miles. Mostly highway miles by an adult driver.
This winter when I decided to do a bunch of work to the car, one of the things was to replace the clutch operating system. Why? Because was only getting about 3/4" throw on the slave by my measurements, was hard to get it into 1st gear from a complete stop, the fluid was brown, muddy in bottom of master reservoir, and I assume it was never changed in 17 years.
Clutch wasn't fully disengaging, so I wanted to make everything external like brand new again...
GM select cable only has 20k miles New GM shift cable adjusted proplerly New GM syncromesh fluid New GM pedal New GM master New GM slave (yes... the real deal, black steel GM slave)
I flushed the line prior to installing the new parts. Bleed procedure was successful. I did bleed the slave several times as a final step removing any remaining air. The pedal feels showroom new. (as it should with all new GM parts) Pedal is high above the brake pedal, no play at all, resistance from the very top..... like I said, the hydraulics is ALL NEW GM and feels BRAND NEW.
Clutch operates fine, shifts into all gears, no grinding at all. The clutch does not slip. There is no fluid leaks. No loss of pressure when holding the clutch pedal in. Visually inspected the clutch arm and looks perfect. It easily goes into gear with engine off. It easily drops into first gear when rolling 3mph everytime. But first gear is still a little stubborn at a complete stop.
I measured the slave distance and still seems to only have 3/4" travel. (unless I'm not measuring it correctly)
Condition seems to get worse if I drive it locally for an hour and get it nice and hot. When you put it into first gear you can sometimes feel the drivetrain shutter ever so slightly. (could be my imagination)I think the clutch is still not fully disengaging.
I really don't want to pull this tranny if I don't have to, especially with no abuse 50k highways miles.
I have made everything like showroom new on the outside, I don't know what else to do.
[This message has been edited by Skybax (edited 03-19-2005).]
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10:00 AM
PFF
System Bot
watts Member
Posts: 3256 From: Coaldale, AB, Canada Registered: Aug 2001
Now go touch the pedal with your pinky and push. Will it move? More air to go! I can't stress enough though - don't push with more pressure than one pinky will do!
It's amazing how sneaky the air can be. I've got a pressure bleeder and can flush the whole system in about 5 minutes. If you've got buddies around there with manual fieros, they're worth it to pick one up!!!
edit: If you DO have air in there... bleed with the slave still off (lets you easily tip it up to get the nipple up high, and you can shake it to dislodge bubbles that trap on the cylinder walls). Then leave the master cap OFF, and in one smooth motion push the slave back into place (with the rod in there). Bolt it back down and you're golden. Save having parts that were worn, I've never had air in a system after doing it this way.
[This message has been edited by watts (edited 03-19-2005).]
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12:33 PM
Rodney Member
Posts: 4715 From: Caledonia, WI USA Registered: Feb 2000
Clutch operates fine, shifts into all gears, no grinding at all. The clutch does not slip. There is no fluid leaks. No loss of pressure when holding the clutch pedal in. Visually inspected the clutch arm and looks perfect. It easily goes into gear with engine off. It easily drops into first gear when rolling 3mph everytime. But first gear is still a little stubborn at a complete stop.
This is a somewhat common condition with the Getrag. Mine does it too. Somedays it is better. Some days it is worse. Some Getrags may not do this or do it very little. Some may be much worse. You may have one that is just on the worst end.
I took the car today to Mark's house (he is a forum member) and lives about 30 minutes away. Thought maybe it would be wise to get a second opinion in person.
Well..... the clutch system worked perfectly all the way there, we went on a test drive it was fine, I let him drive it and was fine, and drove it all the way home it was fine. All stop and go traffic.
We hashed the topic for almost 2 hours. We measured the slave distance again and still come up with 3/4"
How can it be operating perfectly fine with only 3/4" travel on the slave?
A few more notes...
- if you touch the pedal every so slightly the slave moves (good) - if you start it in gear the car doesn't move (good) - if you put it in gear and hold the clutch in the car never moves (good)
Is it possible to have such a great pedal from the very top, have travel all the way through the motion, and still have some air in the system?
[This message has been edited by Skybax (edited 03-19-2005).]
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02:27 PM
Indiana_resto_guy Member
Posts: 7158 From: Shelbyville, IN USA Registered: Jul 2000
Is it possible to have such a great pedal from the very top, have travel all the way through the motion, and still have some air in the system?
In a word, yes.
quote
Originally posted by watts:
Then leave the master cap OFF, and in one smooth motion push the slave back into place (with the rod in there). Bolt it back down and you're golden.
Do that. Or leave the cap on as well as the slave, open the bleeder valve and hand push the slave piston to bottom of cylinder using the rod. Usually air in the system will collect in the slave and doing that will force it out.
Ok... to be honest, I'm not understanding your directions Watts.
If I move the clutch pedal even 1/32" the slave rod moves. Doesn't that mean there is no air in the system?
When I bleed the slave, I removed the bleeder completely, grab the clutch arm, pull it back toward the slave, it moves about a 1/4" and forces fluid out of the top. I hold it there, put the bleeder back in, tighten it down, and let go of the clutch arm.
Wouldn't that be doing the same thing and removing all the remaining air?
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04:08 PM
Indiana_resto_guy Member
Posts: 7158 From: Shelbyville, IN USA Registered: Jul 2000
Ok... to be honest, I'm not understanding your directions Watts.
If I move the clutch pedal even 1/32" the slave rod moves. Doesn't that mean there is no air in the system?
Not necessarily, the air will take pressure to compress. The more pressure added the more the air space shrinks when air is under compression it takes up less space which the fluid displaces.
quote
Originally posted by Skybax:
When I bleed the slave, I removed the bleeder completely, grab the clutch arm, pull it back toward the slave, it moves about a 1/4" and forces fluid out of the top. I hold it there, put the bleeder back in, tighten it down, and let go of the clutch arm.
Wouldn't that be doing the same thing and removing all the remaining air?
Check fluid level first, make sure it is full. Replace cap. Leave the bleeder screw in the housing, just loosen it alittle. Instead of grabbing the arm get a grip on only the rod, with the bleeder cracked open shove the rod all the way int to slave cylinder bore and hold it in. It will go in much farther than just doing the arm thing. Tighten the bleeder screw and fill the master back up and see what you get.
You should be able to grasp it with your fingers. Just start the same way you do with the arm and while you have it at the most travel, release the arm an grab the end of it with your fingers. If that doesn't work well for you use a large wide blade screw driver between the end of the rod and pull it back. It should move freely. While the reasoning of removing the whole bleeder valve is sound, it is also true that there is a greater chance of introducing air into the system in that same large opening of least resistance while reinserting the screw and tightening it back up. I hope that maks sense.
[This message has been edited by Indiana_resto_guy (edited 03-19-2005).]
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08:23 PM
watts Member
Posts: 3256 From: Coaldale, AB, Canada Registered: Aug 2001
Well - I was going to jump back in here (been busy all day!), but it seems IRG has already answered most of what I was going to say anyhow!
It's only a couple of fasteners... take the slave off and check....
Oh yeah, check the pushrod on the master cylinder where it attaches to the peddle. Is the "bump" on the top (which puts the rod nearer the bottom)? That can reduce your total travel as well.
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09:35 PM
Mar 20th, 2005
Gordo Member
Posts: 2981 From: East Guilford, NY, USA Registered: Mar 2002
I had a car the I replaced the clutch after a 4.9 conversion and the clutch felt like crap I did every thingbleeding it still felt like crap,got a pushrod from a chevy engine a 4.3 to be exact and measured it up with the rod from thw slave and made it an 1" longer that solved my problem not saying it is the salution to your problem but just a thought
This is my opinion also Skybax, and the reason for my other clutch thread. IF there is no bent pedal, and IF there is no cracked clutch arm, and IF the system is bled completely-then there should be no need for and adjustable banjo, an extended slave rod, or a reverse pressure valve. And no, I still don't buy the notion that air can enter a good slave cylinder. The return spring pressure of the pressure plate should keep a positive pressure inside the slave cylinder all the time the piston is moving outward or inward. You have an approx 15/16" piston moving fluid back thru a 3/16" line. I don't care how fast you release the pedal, the PP springs are stronger and faster IMO. I'll have to see a slave set up on a bench test with a coumpound gage teed off the bleed screw orrifice and a negative pressure indicated before I can believe a vacum exists at any time inside the slave cylinder. Even with the pedal fully depressed (at a red light for instance) the pressure inside the slave should be neutral at worst, but I still think the PP springs are going to be exerting some back pressure all the way to the pressure side of the MC piston. If this were not true, these problems would have manifested themselves right off the showroom floor 20 yrs ago. Reverse pressure valves, extended rods, greasing the outside of the slave piston area etc are all ad hoc fixes for a problem that didn't exist upon original manufactor. What has changed??
[This message has been edited by maryjane (edited 03-20-2005).]
It's late, and I'm not going into details now but... I gravity bleed my car this evening, got the amount of the remaining air bubbles out I think. Test drive was perfect.
I just got done reading a ton of archive material AGAIN since 1999.
I do not buy the whole "one throw fits all" theory.
EVERY SINGLE post about slave rod travel distance was always one of the following....
- parrots talking ("well I heard") people just repeating what other people have said - muncie 4-sp and isuzu 5-speed distances - never a getrag distance - every time somebody would ask for getrag, nobody would deliver
I think it's partial BS.
You hear over and over..... "you need at least 15/16" for it to work properly"
Or..... "anything less than 7/8" and the clutch won't fully disengage"
Well guess what?
I have 3/4" on an entirely new external GM system and it works perfectly. If what everyone is repeating for the last 5 years is true, than how can that be possible? My car shifts into every gear like butter, no grinding, no pulling with clutch in, no pressure loss, no problems at all. I have a feeling I'm not alone in the getrag family.
I'll tell you what I think.
I think the Getrags have a shorter distance slave throw than the other systems. (like 3/4" forexample, instead of 1" on the other manuals) Like I said previously, out of the hundreds of discussions I covered in the last 5 years, 99.9% of the ones who got those distances were not Getrags.
The VERY few who were not parrots, and who did actually measure Getrag slave throws, with a properly working system, had guess how much???
3/4"
Those few people were doing the same thing I was doing. Had a low mileage 88 GT, with a perfectly working system, new GM parts, bleed the crap out of it, no air, and still get 3/4" and a perfectly shifting car..... and we hash and rehash scratching are heads trying to figure out why we are not getting the slave throw distance everyone claims "everyone" should have.
Arn't the eariler ones 15/16" cylinder bore? And the later ones 13/16" bore? (or the other way around?)
If that is true, how could the infamous "below 7/8 won't work" and "at least 15/16 needed" and "should be over 1 inch" all apply?
Like I said, I'm not buying it. I need more evidence. I'm taking my tape measure to Carlisle, doing a survey, and measureing Getrag slave throws dammit.
I'm going to bed
[This message has been edited by Skybax (edited 03-23-2005).]
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01:46 AM
sardonyx247 Member
Posts: 5032 From: Nevada, USA Registered: Jun 2003
Sardonyx247, I can't have a oval banjo hole bushing, its a brand new GM master. Please read before posting, the entire external system is brand new GM and I am not having any problems. The clutch and shifting operates perfectly.
How can that be possible with only 3/4" slave throw distance? If what everyone has been saying across the board all these years is true, on the Ed Parks site, on Archies site, all through the archives... that everyone needs to have at least 15/16"" minimum, and 7/8" won't fully disengage it, and normal is over an 1"..... how is it that other people including myself only have 3/4" throw on a prefectly working Getrag system?
That defies common sense.
Could it be more bad Fiero specs being throw around for years, just like the wheel offsets?
My gut instinct tell me the "one size slave throw fits all theory" is flawed.
I don't deny the fact the popular slave distance specs are correct for others systems, I'm just not buying it on the Getrags.
Here is one of the more recent threads I discovered...
to answer your question all we have to do is find out the bore of the slaves - that will tell us exactly the throw difference from the getrag to all others.
hmm that thread says 4cyl is 13/16 and 6cyl is 15/16 I can only assume that means isuzu vs getrag - but I thought the getrag slave was visually very different.. wouldn't make any sence for the 4cyl and 6cyl 4speeds to be different unless the clutch arms themselves were different lengths
- 4 cyl is 13/16" - 6 cyl is 15/16" - Masters are all the same size - 13/16 will get you 1.1 or 1.2" - 15/16" will get you 3/4" - The slave on the getrag only has 3/4" travel. I measured everything on the bench, and sure enough, it's 3/4"
So does that mean my 88 Getrag system with all new GM parts having 3/4" slave throw is perfect?
It's worth noting, with all my original parts, and 17 year old brown muddy water infested brake fluid, I had 3/4"
Because according to everyone else, I'm short almost a 1/4"
[This message has been edited by Skybax (edited 03-23-2005).]
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08:17 AM
PFF
System Bot
Alex4mula Member
Posts: 7403 From: Canton, MI US Registered: Dec 1999
I hear you. I'm getting 3/4" to 13/16" max in my tottaly new hyd. system bled to death. Still my clutch supplier tells me I need at least 7/8" (14/16") to work and it seems so after testing.
There was NO WAY multiple people could have all new GM hydraulics on a perfecly working Getrag system with 3/4" throw and something still be wrong.
What's wrong is... the information on all the popular websites (Archies, Ed Parks, etc) and everyone repeating the information on the forum over the years.
Different slaves and different systems have different throws. The "one size fits all" is
Now all we need to do is find out what is the correct throw distance for each system.
Now I can go back to feeling good about my car, because there is nothing wrong with it.
3/4" SLAVE THROW DISTANCE ON A GETRAG IS PERFECTLY NORMAL!!!!!!!!
There... I feel better now
[This message has been edited by Skybax (edited 03-23-2005).]
Correct flow out of the master cylinder depends on travel of the same!
If one person has: slightly thicker carpet, a pedal bent 1/4" down, an ever so slightly sloppy bushing (etc etc) - they might have just that TINY bit less outflow, resulting in the loss of 0.125" (1/8", or the difference between 7/8 and 3/4) of slave travel. Not a lot.
NOW - Skybax - before you go on a rant about IT'S ALL NEW GM, read before you post, etc (way to make friends eh?). THIS WAS AN EXAMPLE. It was ONLY an example, and probably does not apply to YOU. *cough* *ahem*
Now, I know this also isn't the answer(s) you want, but...
Even if everyone's slave travels (eg) 3/4", that doesn't mean that everyones Getrag will/will not shift the same. Might make one guys work great, but someone else has internals that are worn/not worn to a different point and it just won't shift.
There were 3 different part numbers listed (muncie/isuzu/getrag) but only 2 bore sizes (think that got hashed earlier - whatever). No idea why they put a shorter slave on the getrag, but the same bore as the muncie. Not like it effects the travel. Moot point.
I've had rather good luck putting the Isuzu slave on everything! Makes for a firmer pedal, less required 'foot travel' to change gears... and the REAL clincher.... around here it's 1/3 the price!! Yes, I mean it's like 66% cheaper! Only thing is, you have to remove the studs from it and then drill out the flange of the slave (big whoop) to use it on a Getrag.
If you're bored - try it - you'll probably like it as much as everyone elses I've done it to.
I've had rather good luck putting the Isuzu slave on everything! Makes for a firmer pedal, less required 'foot travel' to change gears... and the REAL clincher.... around here it's 1/3 the price!! Yes, I mean it's like 66% cheaper! Only thing is, you have to remove the studs from it and then drill out the flange of the slave (big whoop) to use it on a Getrag.
If you're bored - try it - you'll probably like it as much as everyone elses I've done it to.
*cough* the isuzu slave is the same as the v6 4speed slave - the only 4speed that was different was in 84 it used a different bracket mounting
before you go on a rant about IT'S ALL NEW GM, read before you post, etc (way to make friends eh?).
I disagree. Hey... if somebody gets offended because I said "please read carefully" or "please read before you post" then they are too thin skinned and it's not my problem. It's a public discussion in text.
When I state in my initial post, and mention numerous times, every GM part that was replaced, and the entire system is new, if somebody comes along and says "this might be worn" or "this might be out of round" that means they replied without reading.
It's common on message boards, it's called collective monolog, lots of people talking and nobody listening. I see it all the time.
Some people are offended more easily than others. Unless it is a personal attack, then it's your problem, not the person who said "please read" or "read before you post"
If I had said... "listen up jerk-off, can't you freaking read, are you stupid"..... then you might have a case. But I didn't and I wouldn't because I'm not that rude.
I have MANY friends, and I make them and keep them by being an honorable, considerate, compassionate person.
quote
Even if everyone's slave travels (eg) 3/4", that doesn't mean that everyones Getrag will/will not shift the same. Might make one guys work great, but someone else has internals that are worn/not worn to a different point and it just won't shift.
That's fine... but the point that's trying to be made here is..... everyone states slave travel for the Fiero is supposed to be xxx.
When in fact I am finding that is not the case. You have 1988 Getrag people pulling their freaking hair out becasue the Fiero Gods all say you need a minimum of xxx
Every hydraulic system has a spec, the amount of distance it moves when the system is working 100%, and I believe the 88 Getrag slave isn't supposed to go that far.
Pedal hitting the carpet and other factors have nothing to do with 3/4" travel on a bench test.
[This message has been edited by Skybax (edited 03-23-2005).]
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10:13 AM
watts Member
Posts: 3256 From: Coaldale, AB, Canada Registered: Aug 2001
Originally posted by Skybax: a) You have 1988 Getrag people pulling their freaking hair out becasue the Fiero Gods all say you need a minimum of xxx
b) Pedal hitting the carpet and other factors have nothing to do with 3/4" travel on a bench test.
a) what you need - is what WORKS for your particular car IMHO. Really, who cares what the actual number is? b) but in the real actual world where everyone else is taking measurements - it's a potential factor.
I think it's very important for all the reasons mentioned above.
The same could be said for engine timing...
"if it runs and it doesn't ping who cares what the spec is"
I do. I want it at 10 degrees if that is what the spec is. It's a starting point, a guideline to follow.
If everyone says the Fiero slave should move xxx, and yours doesn't, then it could cost you a lot of time and money looking a problem that may not even exsist, because the information could be wrong and your slave isn't supposed to travel that far.
[This message has been edited by Skybax (edited 03-23-2005).]
Every hydraulic system has a spec, the amount of distance it moves when the system is working 100%, and I believe the 88 Getrag slave isn't supposed to go that far.
based on the movement of the non getrag, and the fact that they all use the same master (or same size master) then its impossible for the getrag slave to move that far (and i doubt its just 88 peolple - it would be all getrags - they all use the same slave
Thank you Kohburn. (I should have said that before when you first mentioned it)
So what I have discovered is true then right?
All the well known Fiero info that everyone follows, all the preaching and advice on PFF, on all the major Fiero sites, by all the Fiero Gods... are all wrong..... is that what your saying?
Hard to believe.
A lot of Fiero owners count on this information to be correct, especially when it comes to something critical like a clutch system. I think a lot of people trust these well known sources because these people spend a lot of time working on these systems. I'm just shocked after all these years it's not common knowledge that the getrag slave throw isn't supposed to go the distance that the others ones do with the amount of manhours involved doing engine swaps, clutch replacements, etc.
So as I currently understand it untill somebody else proves otherwise...
Getrag Slave throw = 3/4" (maybe 13/16") maximum (factory equipped with no mods)
Other Slaves throw = 15/16" to 1~1/16" range
[This message has been edited by Skybax (edited 03-23-2005).]
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11:09 AM
sardonyx247 Member
Posts: 5032 From: Nevada, USA Registered: Jun 2003
The training video could be wrong. I wouldn't be suprised. They stamped the wheel offsets wrong.
What year is the video?
What transmission specificly are they covering? Is it is for the Getrag?
Maybe the tech in the video is using pre-getrag slave throw specs because it was common knowledge?
What about the rare Getrag service book that somebody made copies of not too long ago... (I tried downloading it several times months ago and it would never work) Is there anything in there about slave throw?
[This message has been edited by Skybax (edited 03-23-2005).]
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02:59 PM
Brian27 Member
Posts: 93 From: Maumee, Ohio, USA Registered: Oct 2004
I was able to download the 1987 Muncie Five-Speed Manual Transaxle Manual using FTP software and this is what it states:
"Section 3.3 - Clutch Diagnosis:
Before removal of the clutch hydraulic system, verify the malfunction by measuring the travel of the clutch slave cylinder push rod. With clutch pedal pushed fully to the floor stop, the slave cylinder push rod should travel 9.5 mm (0.374 inch) minimum, 11 mm (0.433 inch) on J-body, against the clutch release lever. Do not replace the hydraulic system if push rod travel exceeds this distance.
If the slave cylinder does not meet the travel requirements, check the resevoir fluid level. The slave cylinder must be in place when checking the fluid level. The proper level is indicated by a step on the reservoir."
Hope this helps...
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04:51 PM
Whuffo Member
Posts: 3000 From: San Jose, CA Registered: Jul 2003
It's also worth considering that the amount of travel necessary changes with clutch wear and condition; two identical cars may need different amounts of slave cylinder travel to fully disengage the clutch.
What is sufficient for one particular car and what is sufficient for all cars of that class are two different things. Extrapolating what's good for all from what works on one is risky logic at best.
Thanks Brian, I don't know if that is Fiero specific, but interesting none the less.
I hear what your saying Whuffo.
But what I'm trying to say and been saying is...
No matter what the conditon of your clutch or trans internals are, the Getrag hydraulic system in itself, in perfect working condition, will only give you roughly 3/4" throw..... not the 1" everyone claimed it should have over the years for all Fiero Manual trannys.
That means hundreds, probablly thousands of Fiero owners with Getrags, might have been lead to believe there was something wrong with their system when it was perfectly fine.
I wonder what the aftermarket Getrag slave cyliner bore is?
15/16 like the original or 13/16 like the other slaves?
If it is 13/16, then the aftermarket Getrag slave would travel 1"
[This message has been edited by Skybax (edited 03-23-2005).]
Did you ever measure the stroke of the pushrod at the master? Knowing the master cylinder stroke together with the bore sizes of both the master and slave (you still have the old ones available to measure, right?) you can calculate the resulting slave stroke assuming no air in the system.
I can certainly believe there will be some variability in the master stroke due to pedal condition, carpet thickness, etc. Your car should be a good data point of reference since everything is new.
and was fine, and drove it all the way home it was fine. All stop and go traffic.
