Technical Uneven Clutch

vladof · Oct 20, 2010

Hi everyone,

By now I think most of us know there is a dead point on every Stilo clutch. I'm not talking about the point from when its down to where it bites, but the point from where it's sitting when not pressed to where its actually starting to move the piston.

My dilemma is: On my Stilo, when I first bought it, I noticed that the clutch had a relatively high biting point (55-60% up) but was smooth as a whistle and didn't seem to be worn so I figured it was ok. After owning it for about 2 months I've noticed something rather strange. If I drive in heavy traffic and I use the clutch a lot, the gap between where the pedal stands and where it actually begins to move the piston is getting larger, thus the clutch bites at about 35% because the rest of the course is dead end. Even weirder is the fact that after letting it undriven for about an hour everything is back to normal.

The other Stilo has the same biting point always regardless of how much I use it in traffic. I'm worried that one day it will move so down that I will be stuck in gear and forced to cut the engine to stop.

Sorry for the large topic but I couldn't really find any words to describe this easier.

I would very much appreciate any suggestions whatsoever.

Cheers to all.

schumraid · Oct 20, 2010

Sounds like a master cylinder packing in, how many miles does the car have?

vladof · Oct 20, 2010

76000. Is it expensive to replace?

If it was the master cylinder, should it still be working fine after leaving the car parked?

I believe it's a 500 pounds job to change the whole structure, so if its that I'm kind of screwed.

Deckchair5 · Oct 20, 2010

Try bleeding the clutch hydraulics. A moving bite point as the system heats up and going back to normal again after it cools sounds like poor hydraulics

schumraid · Oct 20, 2010

little early for it but then again this is my first Fiat

. If a seal is on it's way out I think it's very possible to suffer the symptoms you described. Also if it's just a seal you can have it refurbed for a lot less than £500.

Sorry I've never worked on one myself so I can't be of more help, I found this on checking the cylinder though:

"One check you can perform on the master cylinder is to depress the clutch pedal while someone watches the brake fluid reservoir level. If the level rises while the clutch pedal is being depressed, The clutch master cylinder is bad and should be rebuilt or replaced."

vladof · Oct 20, 2010

I just went down and gave it the whole repsol chain lube (half of it was already on the other Stilo's clutch), and it's smooth and easily pushed with 2 fingers. Another question I have if you would be so kind to answer, would it make any difference if I lubed the portion described by the arrow in the attached picture?

My narrow mind thought that maybe a valve or something from one of the cylinders is stuck and if I were to lube over there it would get near the slave or master cylinder (don't really know which is first) and maybe solve my problem.

Anyway, now that it's very well lubricated I should be able to get a clear thought when and if it fails tomorrow morning. If it does, first thing I'll do is go to the guides section and proceed on bleeding the clutch.

Thank you all for your help. Any other confirmations or opinions are gladly encouraged.

@Minus8: I will also try what you said mate.

Wouldn't know what I'd do without you guys.:yum:

vladof · Oct 21, 2010

Just arrived to work this morning. The clutch definitely needs bleeding, I think.

It's never too down to grind, just that the biting point moves and about 30% of the course is dead aka not moving any cylinder.

I've also noticed that if I leave the car even 10 minutes, it goes back to normal. After that, I went in the car and pedaled the hell out of it and after about 20 goes it went back to being down and having a large dead point until it moves the piston.

I still have other questions that I would appreciate an answer to:

I found Deckchair's guide on how to bleed the system.

1. Removing some hydraulic fluid from the circuit wouldn't mean creating a larger gap thus a lower biting point because there isn't enough fluid to keep the hydraulic rod fully up?

2. Also, I've noticed in the guide you said that I should top up the brake fluid. This means they share the same system doesn't it?

3. How do I know which type of fluid to buy? Can they be mixed? I have no idea what is inside.

4. And the last one: after bleeding the whole system is there a chance that the clutch will be fully up and start pressing on the cylinder immediately after pressing the pedal?

5. What's the worse that can happen if I do this?

schumraid · Oct 21, 2010

vladof said:
Just arrived to work this morning. The clutch definitely needs bleeding, I think.

It's never too down to grind, just that the biting point moves and about 30% of the course is dead aka not moving any cylinder.

I've also noticed that if I leave the car even 10 minutes, it goes back to normal. After that, I went in the car and pedaled the hell out of it and after about 20 goes it went back to being down and having a large dead point until it moves the piston.

I still have other questions that I would appreciate an answer to:

I found Deckchair's guide on how to bleed the system.

1. Removing some hydraulic fluid from the circuit wouldn't mean creating a larger gap thus a lower biting point because there isn't enough fluid to keep the hydraulic rod fully up?

2. Also, I've noticed in the guide you said that I should top up the brake fluid. This means they share the same system doesn't it?

3. How do I know which type of fluid to buy? Can they be mixed? I have no idea what is inside.

4. And the last one: after bleeding the whole system is there a chance that the clutch will be fully up and start pressing on the cylinder immediately after pressing the pedal?

5. What's the worse that can happen if I do this?

1) If the biting point is currently excessively high, yes it will drop it, with excessively low fluid levels your biting point will hit the floor, with hydraulic clutches being self adjusting it will effectively try to do what it thinks is best.

2)Yes

3)DOT4 Brake fluid. Topping up with DOT4 will be fine unless your fluid is excessively dark, in which case I'd flush the system through with new fluid.

4)If an airlock/air in general is your problem and you solve it correctly then yes

5)If you mess it up you'll not be able to drive the car until it is bled and refilled properly

vladof · Oct 21, 2010

Excellent. I will buy the fluid and start the process as soon as we get some kind of break from this weather.

Thank you very much for all your help. I rest assured that I can't really brake anything too expensive so I'll try that.:yum:

Wouldn't it be a good idea to check for the fluid level before any kind of DIY thing?

schumraid · Oct 21, 2010

Good luck

. You can't really break anything (unless you completely drain the system and try and ram it into gear I guess

).

The brake reservoir should have min/max filling points on the side of it so just make sure your within those limits when your done

.

Hope this sorts it!

Deckchair5 · Oct 21, 2010

The Stilo Guides refer to a 1.6 engine and the 1.2 and 1.4 engines are similar

but the 1.8 engines have a concentric internal slave cylinder so the bleed point is much further down and some have had trouble evn finding it

I hope not but if you have to keep bleeding it then obviously air is getting into the sytem and it's more often the slave cylinder at fault

vladof · Oct 21, 2010

Ah, drat. Do I need to take anything off?

I'm pretty sure the clutch was like this ever since I bought the car, but I had the other one in Bucharest with me for two months while this one was registered in my home town, 500 km away, and pretty much nobody drove it. So basically it was always like this, and nobody did anything to the poor car, I'm pretty sure the clutch never saw a bleeding in his life.

If it is, let's say, the slave cylinder, is it costly to repair or change? I've read about costly operations that required a lot of engine parts to be taken out. It will take me back at least 200£, won't it?

Deckchair5 · Oct 21, 2010

I think it's reasonable accessable once you get tubes and stuff out of the way

But, yes, if you have to keep bleeding it because air is getting in then you'd need to most likley replace the slave cylinder which, because it's inside the clutch housing would mean gearbox needs to be moved out and that costs a lot in labour as they will often say it's worth changing the clutch assembly too unless it's quite new

If it's been lke that all the time since you've had it and not getting worse then you may be lucky and it just needs bleeding

vladof · Oct 21, 2010

Thanks. I'll give it a go on Saturday. Hopefully I'll sort it out.

If not, I need to go back home to get it serviced. Bastards here quoted 600 Euros for the clutch kit.

vladof · Oct 21, 2010

I came home a little earlier today and figured out I might as well give it a go, the instructions did not seem very hard.

Turns out I'm really stuck. I've opened the battery cover, and with the printed instructions I tried to find the bleed nipple. I couldn't find anything that even remotely resembles the part i should be disconnecting. I'm thinking it's more and more a dealer's job, and if it's something simple I should be able to run out with only 20 pounds fee.

I've posted some pictures of what I saw when I opened the battery cover.

Can somebody please direct me to the right place?

Also, because it was almost dark when I made them, after downloading the pictures I saw there is some kind of leak from the part pointed by the arrow in the last picture. What is that?

Deckchair5 · Oct 21, 2010

This is a concentric slave cylinder bleed nipple on a JTD
Just follow the clutch hydraulic hose down and it'll be at the end of that

If it's never been touched before then it'll have a plastic cover on the nipple like this one

vladof · Oct 21, 2010

You're gonna kill me for asking so many questions, but this is me trying my luck:

1. I'm even having trouble finding the clutch hydraulic hose, can you please point out on one the the images I've just uploaded where approximately could it be?

2. After finding the hose and the bleeding nipple, I should simply follow the steps you've mentioned in the guide, right?

3. Can you make anything out of the picture with the arrow in my previous post? Is that a leak or something else? What is that part?

I can't even imagine the number of beers I owe you.

Thank you very much for your indispensable help.

Deckchair5 · Oct 21, 2010

It's a little tricky as everything is in a different place on lh drive car than we're used to here.

But this hose from the brake/clutch hyd reservoir will lead straight down to the clutch master cylinder

It looks like you have a rigid metal pipe rather than a flexible hose which leads from your clutch master cylinder to the slave cylinder

concentric slave cylinder pipe guard.JPG

And this pipe guard above your slave cylinder may be obscuring your view

Davren · Oct 21, 2010

The brake and clutch systems share the same fluid resevoir as a safety feature. The clutch supply pipe it located part way down the resevoir so that if there's a fluid leak from the brakes, the clutch will stop working before the brakes do.

The clutch master cylinder supply pipe for your LHD 1.8 is the one with the yellow arrow in the bottom picture. If you follow it, it will go to the clutch master cylinder which should look something like the first diagram.

The only other pipe on the clutch master cylinder (1b in the first diagram) goes to the concentric slave cylinder which is inside the gearbox. You may need to remove the metal plate shown in the second diagram to see where the pipe goes into the gearbox.
.

Davren · Oct 21, 2010

Decks beat me to it again.

My yellow arrow is infinately better than your red one.

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