Hey Patrick, BTW I liked your joke way back 'bout a million posts ago I just didn't say so!

Geez Ozzy, you had to mention that joke. Shortly after I posted it I wished I hadn't. If there was an Edit function at this forum, I'd have removed it a long time ago. I realize it's not that crude, but it's still not called for in a forum such as this...

((With the change in the forums on Sept 7th, I was able to rewrite history and remove the "joke". Hey, it wasn't that bad, but...))

Anyway, let's talk clutch. Many people (including myself originally) have been of the mistaken impression that if a longer rod is used between the slave cylinder and the clutch lever that somehow the clutch throw will be increased. As I reported much earlier in this thread, I used a "variation" of this idea and moved the slave cylinder closer to the clutch lever. This does NOT result in the clutch lever being repositioned at all. It is the slave piston which becomes repositioned. The ONLY reason why this might make some difference is because the piston and seal are now positioned further back INTO the slave in a slightly less worn part of the cylinder. This could possibly result in better sealing IF there had been a problem with sealing in the "worn" part of the cylinder. Paul's idea of the second piston accomplishes this same thing, with the advantage of it also adding a second seal.

When the clutch pedal is depressed, there is X amount of fluid displaced from the master cylinder. The fluid is then forced through the hydraulic line to displace an equivalent amount of fluid in the slave cylinder. Bore size is not necessarily the same, but if it is the same in each cylinder, the slave piston will travel the same distance as the master piston. The slave piston will travel this same distance EVERY time, no matter from where in the cylinder it starts. If the slave piston is designed to travel distance Y, no amount of messing about with rod length is going to change that. (Except as noted in the previous paragraph.)

Earlier in this thread, there was some mention of other possible alterations, but if ALL of the air has been removed, a properly functioning factory set-up WILL supply enough travel to disengage the clutch properly.

I can't emphasize enough that it is air in the system that causes so much grief.

[This message has been edited by Patrick (edited 09-07-1999).]

Id like to add my input into this thread. I like this idea of substituting ATF for DOT 3. I once tried using DOT 5 but it didnt work out well. Ive still been having clutch problem over the past months. One neat trick I came up with since my double piston idea was to remove the rubber seal from the slave piston, then wrap the inside of the groove with teflon tape. When you put the seal back on, it will be slightly expanded. This is better than buying a rebuild kit everytime. What Ogre said earlier about side-loads on the slave piston is true. My release arm was really twisted. I could hear the piston scraping against the side of the slave. I had to take the arm off and pound it back into shape. Also drilled and installed a couple of nuts and bolts to make it keep its shape. When I put it back on, I could tell the side load was still there. Pedal felt hard and the scraping sound still could be heard. I had to mess with the arm somemore, prying it until it looked straight, still couldnt get it right, said f*ck it and jumped in, drove off. After a few miles, the pedal suddenly felt soft, thought I was loosing fluid. But the clutch was working great. I guess it straightened itself out.

I'm gonna have to get a damn cable modem or T1 line just to download this thread soon!

Patrick, I bled about 30 gallons of ATF through that thing today (well, almost 30 galls.) and if there is mo' air it ain't coming out to play! The cleanup of the system seems to have worked in fixing my 'clutch only when warm' syndrome though.

After applying my theory of Quantum mechanics (The dreams stuff is made of!)I also concur on the displacement argument. Now the only thought I have to maximizing the full use of master cyclinder volume is to place a spacer between the rod and master piston. X ammount of pedal movement will also give the equivalent ammount of piston movement but my pedal can move back about 1/2" from being even with the brake pedal. All I have to watch for is that I'm not bottoming out the master piston in the cylynder and that "should", and I use the word tentatively, give me a little more pedal.

PaUL; It's hard for me to comment on the ATF substitution given that if you saw the **** I drained out yesterday, swamp mud would have been an improvement. The pedal feels solid and true. I should think, as others have mentioned above, that the viscous qualities alone should help to seal and lubricate the cylyinder walls better. Plus it's a pretty RED!!! (Wry smlile) Can't seem to plaster those damn smilies on here. Do I need to start ANOTHER thread on this??

Ozzy (wink, right on hand signal, victory sign, thumbs up sign, etc, etc, etc!)

Ozzy, are you saying that if you were to pull the pedal back towards the seat that there would be half an inch of clutch pedal travel before the rod actually starts to make contact with the master cylinder piston? That doesn't sound right. I'll have to check mine tomorrow, but I'm pretty sure that there is absolutely NO play at all.

I hope you exaggerated a little the amount of ATF that you flushed through your system. Thirty gallons??!!! Was that in US or imperial gallons? I think I was able to flush out my system completely with about half a litre of ATF. That was after I sucked the muck out of my master cylinder reservoir with a turkey baster!

When the clutch pedal is even with the brake pedal the rod is contacting the rear of the piston. My point is that in fact my clutch pedal moves toward the seat at least another inch. Now obviously It would be uncomfortable to raise the clutch too high but I would live with 3/8" or so if it gained me a little more pedal. I will experiment some more.

Uh, Aussie gallons dude!
At least 300 gallons o' ATF! The only air left on that bad boy is in the tyres!

Yee Harrrr! I can post a I can post a

[This message has been edited by Ozzy (edited 09-08-1999).]

Geez, this thread is still going? 3 pages worth. By now we could have just completely redesigned the system and retrofitted our cars.....

Man, this friggen clutch...

As I reported here, I changed over to ATF in my clutch hydraulic system. Everything's been peachy for the last week, the clutch has been disengaging cleanly. I can't remember the last time it's gone for a week and continued to work perfectly. However...

I was driving the Fiero yesterday, the clutch felt great, and then all of a sudden the next time I stepped on the pedal it almost went to the floor before it barely started to disengage the clutch. Of course, the clutch would not fully disengage any longer. I pulled off the road, bled a ton of air out of the slave cylinder, and carried on.

Because of the fact that I have NOT rebuilt (or replaced) the slave yet, I'm not surprised that air can be drawn past the seal into the cylinder. What DOES surprise me though is that it appears to happen so suddenly. The air did NOT get drawn into the system bit by bit until the clutch no longer worked properly. It went from NO air in the slave and working perfectly, to a LOT of air in the slave and being useless, all in the space of ONE SHIFT!!!

I have an 87 gt with 5speed manual. My problem is, it is difficult to shift into 3rd gear only, it makes a grinding sound in the transmission. 3rd is the only gear that gives me this problem the rest shift smoothly. I would appreciate any advice.

That sounds like syncros to me.

C'mon guys, 100 posts by X-mas!!

Week 2 with the ATF transfusion and no signs of rejection yet.

Ozzy

Just wanted to see what I was missing;the last post I can read/view was done on 4/14.
Thinking maybe this post would change the situation(?)

Well, back again gents... bled the system and still pedal does not hold compression... sooooooo.... tomorrow i am going to rebuild master cylinder. lets see if that works... Strange thing is, i drive about 15 miles from home to work, and 15 back, the clutch problem seems to start at the end of the 15, after i have been up to speed for awhile. Any comments on this guys?

Unless you suspect your master cylinder for some particular reason, my comment would be that your problem is at the other end of the system. My clutch hydraulics have also exhibited problems after the car gets real warmed up. I believe it may have something to do with the slave cylinder and the fluid in it getting good and hot back in the engine compartment. However, this seems to be less of a problem now that I've changed to ATF in the system.

The other reason I suspect that the problem may be at the slave end is that in my case, I replaced the master clutch cylinder when I first got my Fiero. It helped, but it far from cured the problem of air entering the system.

Is your problem also the fact that air is getting into the system? Does the air enter at the slave? This is usually pretty easy to tell because air bubbles will come out as soon as you start to bleed the system. If air was entering at the master cylinder, I would think that it would take a while for this air to show when the system was being bled.

But who's to say? I've been banging my head against the curb for so long with this problem that I can no longer think straight. But I'm still smiling...

oookey...so how does one get the spring assembly out of the cylinder?... by the way ...there was mud (or what passed for mud) all through the cylinder

I have had the same problem with my 87. Iwould bleed it almost every other day, I just couldn't get all the air out of it. I finally got really pi**ed off one day and jacked the back of the car up till the bottoms of the tires were about 6 inches off the ground and then bled the system. It seems to have helped, at least in my situation. I have not had to bleed it in over a year now and had no problem since.

The size of this thread proves that the fiero hydralic clutch system was poorly designed and contructed. Is there a way to convert it to a cable system? Maybe someone will come out with a better slave, I would think there would be alot of demand for it.

I was just thinking, kong, that if your first name was king, you wouldn't have to attach that one inch piece of wood to your clutch pedal. Sorry, I couldn't resist.

I can't speak for all the others here who have clutch problems, but I certainly don't have any trouble putting the pedal to the floor. As a matter of fact, I even peeled back the carpet and removed the underfelt from below the clutch pedal so that when the carpet was put back, the clutch pedal could get a bit more travel. Every little bit helps.

[This message has been edited by Patrick (edited 09-16-1999).]

When I bought my 84 the owner said it had a bad slave cyl. Also the clutch pedal was bent,so I replaced the pedal and was going to rebuild the slave but it works just fine. I put at least 50 miles a day on the car and I haven't had to bleed it yet. Looking at the slave cylinder,it doesn't look like it is original. According to the manuals and what I have read here,the Fiero slave has 2 bolts on the end. Mine has a flange on the cylinder and is bolted to a bracket. I'll try to get a picture of it and post it. But alas I have no idea what it is off of.

You have the type 1 cylinder used on eariler Fieros. My '86 has the type 2 master and slave.

Type 1 ?

Type 2 ?

I knew that my master cylinder looked different than what is pictured in the Haynes manual, but I was unaware that there was a difference in styles of the slave cylinders for the Fiero.

Please tell us more.

I had a '84 parts car and it had the slave cylinder that used the side mounts along the length if the body. My '86 has the flange on the end of the cylinder. When I go to NAPA to buy hydraulic parts for either the master or slave cyl, they always ask if I have the type 1 or the type 2 cylinders. This may be just something that NAPA uses to differentiate between the two designs. Reguardless of what they're called, there are two different types.

Apparently there are 3 slave cylinders used on Fiero's. 84's had the flange on the body.I 85 there is a slave cyl for the 4 spd and Izuzu 5 spd and a different one for the Getrag 5 spd. At least that's what the computer at Knecht's Auto Parts shows. Could it be possible that you are getting the wrong rebuild kit?

I think there is a heck of a lot of confusion about a lot of things when it comes to buying automotive parts. All too often we're forced to deal with an uninterested individual making minimum wage who couldn't give two hoots whether he sells us the correct part or not.

This is an unusual move, but this thread is so long that I'd like to repeat an experience of mine that I posted near the beginning of the thread which is relevant to what we are discussing here now. Forgive me, but not everyone has read this thread from the beginning.

"I'm having a problem trying to find the correct clutch slave cylinder for my car. It's a 1987 Pontiac Fiero with a 4 cyl. 2.5L engine and the 5 speed manual transmission made for Pontiac by Isuzu. The part number in the Raybestos catalog is NPN SC37794. As soon as I saw the Raybestos cylinder I could see that it wouldn't work. Right off the bat it was obvious that the rod that reaches to the clutch lever was too short. (It was about three inches long instead of six.) When the dealer insisted that it was the correct slave cylinder, I simply used the rod from the old unit. Unfortunately this did not help. It turned out that the bore size of this new unit was 15/16 inches whereas the original GM slave cylinder has a bore size of 3/4 inches. As you can appreciate, this makes a difference when dealing with hydraulics. The larger bore size of the new cylinder prevented the clutch lever from being moved as much when the clutch pedal was depressed. This of course led to the clutch not fully disengaging. The dealer took back the cylinder but still insisted that it was the correct one and that I had the WRONG TRANSMISSION in the car. Anything to save face I guess. So at this point I'm still limping along with the old slave cylinder."

That was an excerpt from an email that I had originally sent to Raybestos two years ago. They never bothered to respond. Pardon my language, but screw 'em.

Patrick, the kit you got with the 15/16 bore was the one for the 5 spd Getrag. The bore on your cylinder should be 13/16ths. You don't have the wrong tranny they got the wrong part #. I'll check the part number at my parts store and send it to you. Maybe that'll help the jokers get the right part for you. If notheing else I can get it for you and send it to you.

Hey Glen, I know that I don't have the "wrong" transmission in the car. I was simply dealing with the wrong person at the parts counter. When I told him that the different bore size of the slave cylinder he supplied would make a difference in how the hydraulic clutch system would work, he just sneered at me and basically stated that I didn't know dick-all. I don't mind anyone disagreeing with me, but this guy was such an arrogant bastard that I never returned to that store again. And it was a store with very good prices. Let that be a lesson to all the retailers out there. Low prices are NOT everything. Knowledgeable, friendly service is also a necessity.

I'm quite positive that the bore size measured 3/4 inch. Are you sure about that 13/16 inch size? I would still like to get a rebuild kit for the slave that I have, but now you've got me wondering whether or not I'll have a problem getting the right one. Luckily my clutch is working pretty good now since the ATF transfusion, but if you could send me some part numbers (with matching bore sizes) that would be great. Thanks.

O.K. so 200 posts by x-mas!!?

Hey Patrick...did you ever check the pedal movement on yer Fierjo? Does the pedal come back toward the seat? My ATF transfusion also has been working fine.

Only trouble is now the car is down due to the automatic belt tensioner shitting itself. But that is another thread.

Ozzy

Having the correct part numbers for any car can be a very valuable tool. I too have found the automobile/part knowledge of many a counter person to be less than desirable. In that, I would like to share a link that I have found VERY useful. If nothing else, you can at least arm yourself with some upfront information before attempting to locate the correct part.
http://www.weekendmechanicsclub.com/Home.asp

BTW, I found seven entrys for the various clutch slave rebuild kits using this site.

Patrick,here are the part numbers. They are for Wagner parts-Slave cylinder # WAH F103482
Rebuild Kit # WAH F103554. Next your going to ask for the prices....well the cylinder is around $90(US) and the kit is around $15(US). And according to the computer it is a 13/16" bore on your slave. I hope this helps.

Ozzy, I checked my pedal and it barely moves towards the seat. Maybe a quarter inch maximum. That bit of slack could probably be taken up with a new bushing where the rod attaches to the pedal mechanism. If you have more play than that, there must be something else worn or bent in your car.

Mike, thanks for that informative site. It's great.

Glen, thanks for getting those numbers and prices. I know you said not to quote you on your prices, but is their any chance that the price you gave for the slave kit is correct? It appears to be less than half of what any of the places listed at Mike's site charge.

It also appears that I must have been wrong about the bore size. Damn, I guess I'm human after all. I could have sworn that the bore size was 3/4 inch, but yes, all indications suggest that the choices are either 13/16 inch or 15/16 inch. I also notice that the listing for the Raybestos slave cylinder does NOT differentiate between the Isuzu and Getrag transmission for my car. The only choices that are given are for either a 4-speed or a 5-speed. The jerk that I was dealing with at the auto supply shop got the "right" one for me according to the catalogue, but that doesn't excuse his arrogant attitude when I informed him that it wouldn't work with my Fiero.

I wonder how much difference, if any, there is in the quality and/or the functionality of the different brands of slaves and kits. Is there anyone out there who swears by the GM replacement part(s). It's a relatively simple device, but if there is a difference to look out for, it would be great for a lot of us to hear about it in this thread.

The prices shown for the parts at the mechanics club site I posted are usually incorrect, they are nearly all quite a bit higher than you will see at your local autoparts store. I am not sure as to the reason for these discrepancies, but the part numbers have been very accurate. So disregard the prices and all should be well.. I should have mentioned this in my post, sorry for any confusion this may have caused. :-(

Mike

Patrick,I checked around and the best price for a rebuild is $42. Was I ever off on that,the kit for mine cost 15,ergo the mistake. But I found a slave cylinder for $76. It is at Pep Boys..I don't know if you have those up there. I would be happy to get one or the other for you,just let me know.

Thanks for the offer Glen, but with the US/Cdn exchange rate the way it is, it's probably cheaper for me to buy these auto parts here. Plus I'm curious to see how long my hydraulic system is going to work properly after the ATF transfusion. Except for the one negative experience I reported in an earlier post, the clutch has been working great!

Patrick

What was the hydraulic problem that you reported a week or so ago? Was it the slave cyl that you thought?

The problem that I posted on 09-08-1999 was simply more air again in the system. It appears to enter at the slave because when I bleed the system the air bubbles out immediately. The clutch has worked fine since that day.

I just want to thank you David, for being the first one here to suggest trying a different fluid in the clutch hydraulic system. It may not be a cure-all for every problem, but it sure has made a difference in the way my clutch works so far.

It makes me wonder why DOT3 was ever the designated fluid to use for this application in the first place.

I installed a new clutch in my 84' in 3 hours
with only a floor jack.

I also replaced my fork after realizing that
my thowout bearings were consistanly chewing
through the pressure plates. The bearing was
always coming off the fork. That is what happens when you pay a clutch shop to install. Do you think they care?...NO!

Also...this gentleman named patrick is having
all these hydlaulic problems. Hmmmmm....this
reminds me of all the problems I had. Try
examining the distance your pushrod in your
clutch master cylinder has to offer with your
clutch pedal. Mine clutch pedal assembly was
off and this allowed air in the clutch master. I fixed it with a simple lock washer.
Never had to mess with it since. And after
reading all these replies in this chat room, it takes me way down bad memory lane with all
the same problems that I had. Now I can finally say that I have the best problem free
smooth shifting fiero in the world.
Bye for now..................................