(G) stilo clutch problem

Thanks Decks. I understand what you say about the slave cylinder throw, I'm just clutching (pun ) at straws now. I'm hopping that the slave cylinder isn't operating to it's full extent (maybe because it has air in that I can't bleed out) and by getting a little bit more travel on the master cylinder I may be able to get the concentric slave cylinder to extend a bit more.

The clutch pedal is coming up fully and resting on it's stop (the clutch pedal switch).

I discarded the panel a while ago when the brake switch needed adjusting every few days. There seems to be quite a lot of play in the clutch pedal and I've tried tapping the master cylinder a few times thinking the piston may not be fully retracting but it's resting on a circlip inside the cylinder so can't retract any further. Hence the idea of trying to extend the push rod.

On the face of it, it would appear that the carpet is the problem. If I press the clutch pedal 'normaly' I can't engage a gear, If I force the pedal down into the carpet I can just about get one, and there is a large indentation worn into the carpet where I and the previous owner have been doing this. The answer would possibly be to cut a slot in the carpet which I don't really want to do.

It would certainly be a lot easier with an external slave cylinder, then I could just try the old trick of putting a dome-nut between the piston and push rod to get a bit of extra travel.

Dave.

A car where you have to put the clutch absolutely to the floor every time you change gear is a real pain and is enough to give anyone back ache. It's such a difference and a real pleasure to drive if the bite is somewhere near the middle of travel

Thing is that Stilo clutches are different in design for so many models so it's difficult to generalise but all hydraulic operated clutch systems are non adjustable. It's understandable you'd think that putting a spacer in at the slave cylinder would make the travel further but it doesn't. As soon as you release the clutch then the slave cylinder piston is pushed back to where it was originally MINUS the spacer length and then you're back to the same length of travel as you had in the first place. It doesn't make the range of movement any larger.

It's getting a greater range of travel that you're after, so unless your slave cylinder has bottomed out and reached the end of its travel ( and you'd feel that by the pedal going solid) then a spacer wont do anything

So yes bleeding the system and new fluid are first point of call
Then, wear in the pivot points at the master cylinder or clutch actuating arm at the slave cylinder end will cause lack of movement
Wear in the slave cylinder or master cylinder seals cause problems but this would be noticeable by the clutch slowly engaging on its own

If you pump the clutch does it get better then?

I know you have checked but really make sure the clutch pedal is getting to the fully up position, the last few mm make all the difference

There's also the possibility of an actual clutch problem in not disengaging

Do a search as i remember someone else had a lack of clutch range of movement on a Stilo diesel

I would have thought that all hydraulic clutch systems are self adjusting. There needs to be a means of compensating for wear on the clutch disc the same as with a cable operated clutch that has either manual or automatic adjustment.

In my case, the idea of putting a spacer on the master cylinder push rod is to eliminate some of the exccessive free play at the pedal. I'm guessing (hopping) that the extra travel of the master cylinder piston will pump a greater volume of fluid to the slave cylinder thus increasing it's travel. I've successfully used this method in the past when replacing clutches on (showing my age now) old BMC transverse engine cars. We often used to put a dome-nut on the slave cylinder push rod. I still recall going to the local bicycle shop to get a supply of them.

There's no wear in the pivot points at the master cylinder. As already mentioned, my main concern is the exccessive free play at the pedal. Pressing the pedal from it's rest position is having no effect on the hydraulics for the first few centimeters of travel. The pedal is getting to it's fully up position and resting on the clutch pedal switch. The switch is similar to the bake pedal switch so I can lift the pedal higher against the switch ratchet but that would only aggravate the problem by increasing the free play.

There are no pivot points with the concentric slave cylinder. The cylinder is bolted inside the gearbox and fits around the gearbox input shaft sleeve so the cylinder operates directly on the clutch release diaphragm (picture below).

When I bought the car 2 months ago, pumping the pedal worked, I bought the car thinking it just needed bleeding, but now it makes no difference.

If my spacer in the master cylinder idea doesn't work, then I'm going to have to look at the clutch itself. The car has done 80,000 miles and has never had a new one. I actually bought a new clutch from Fiat a few weeks ago but was hopping to keep it as a spare for when I go to Greece for the summer next year and fit it there. According to eLearn, the engine has to come out to fit a clutch and I don't have the facilities to do that here. I know the people in the Fiat garage where I go in Greece and would be able to do it in their workshop.

I tried a search of the forum but as the search function on the site only searches for individual words and not text strings it comes up with thousands of unrelated pages with the word 'clutch' in.

Thanks for your input so far Decks.

Dave.

I would have thought that all hydraulic clutch systems are self adjusting. There needs to be a means of compensating for wear on the clutch disc the same as with a cable operated clutch that has either manual or automatic adjustment.
Yes all hydraulic clutch systems are self adjusting (or should be), they are just not manually "adjustable". Self adjusting cable operated clutches often don't self adjust properly and can be altered manually with some persuasion and interference

In my case, the idea of putting a spacer on the master cylinder push rod is to eliminate some of the exccessive free play at the pedal.
Yes getting rid of free play at the master cylinder end means more stroke and increasing the range of movement

I'm guessing (hopping) that the extra travel of the master cylinder piston will pump a greater volume of fluid to the slave cylinder thus increasing it's travel.
Yes that's right, greater volume of fluid moved means longer movement at the slave cylinder end


I've successfully used this method in the past when replacing clutches on (showing my age now) old BMC transverse engines. We often used to put a dome-nut on the slave cylinder push rod. I still recall going to the local bicycle shop to get a supply of them.
No, what you were doing there didn't increase the range of movement, it just moved it. What happened on old BMC engines was the slave cylinder got to the end of its stroke and STILL it wouldn't be enough to disconnect the clutch properly with wear in all the other moving parts so by putting in a spacer there you moved the range, you didn't increase it, just moved it. The range of movement was always fine, it was just in the wrong place.

Your slave cylinder hasn't reached the end of its travel or "bottomed out", if it did your clutch pedal would go rock hard before it reached the carpet

Working on the master cylinder end and eliminating free play there WILL increase the stroke and therefore longer movement at the slave


When I bought the car 2 months ago, pumping the pedal worked, I bought the car thinking it just needed bleeding, but now it makes no difference.
If it pumps up then it's a hydraulic fault, if it makes no difference then it'll be more mechanical

I think you're on the right track, look for loss of movement at the master cylinder end, maybe a worn pedal pivot?