Technical Loosing clutch/brake fluid periodically

[penguinpaul]

My Stilo has been good as gold for quite some time, but now it looks like I may have an issue..

Backstory:
About a year ago, I drove about 50 miles, and then did some city driving, at which point I lost my clutch pedal. It started going hard, and then went down to the floor and stayed there. (Still with drive though)
Turned out that the fluid level had dropped.. after a top up, everything was fine again.

Since then, I've been keeping an eye on the fluid level, and it has stayed there at max, no issues.

This weekend, I set off for a local festival. (Boardmasters for those interested! Jamiroquai were incredible )
Checked all of my fluid levels the night before.
As I got there, I was in fairly slow traffic for half an hour. Just as I got there (luckily in the parking field!), I felt my clutch go hard
Luckily it came back enough for me to park. Checked my fluid, and yep, down quite a bit, an inch or so down the header. (Must be around/on the min)
As it cooled down that night, I was able to drive home ok.

Any ideas what this could be? It seems really strange that it's not a gradual leak of fluid. It went a year between these times without loosing any, but then decided to loose a lot in half an hour of traffic.
I certainly had a false sense of security from the last year of it being fine! I'll be keeping some fluid in the boot...

 

[Ralf S.]

The clutch slave cylinder sounds a bit marginal.

Some Stilo's have a bone-shaped cylinder on top of the gearbox and it's a dead easy swap and re-bleed... but others have a Concentric Slave Cylinder (CSC) which is fitted onto the inside of the gearbox bell-housing. The latter is a gearbox-off job.

If you need a new clutch any time soon (how many miles has your current clutch done?) then buy a new CSC and have both fitted at the same time. Quite frequently people/garages change the clutch but not the CSC since it isn't leaking, or because no CSC is supplied with some clutch kits.. but it's a false economy to spend £300 on a clutch change and skimp on £40 of additional component.

Ralf S.

 

[penguinpaul]

Thanks Ralf, it's a 2003 1.6 petrol. Really hoping it's an external slave cylinder if that could be the culprit, as it had a new clutch only 15k miles ago!

Does it seem odd that it's not a gradual leak? Or is it just something that can happen like this?

 

[penguinpaul]

This looks promising:

https://www.shop4parts.co.uk/?name=store&op=Details&ProdID=18314&sku=262165

I'll try and have a look tonight if the rain stops, and see if I can see it - and if there's any fluid around it.

 

[Ralf S.]

If this is your car, then it looks like an external one:

http://www.ebay.co.uk/itm/Fiat-Stil...650237?hash=item464f26bfbd:g:a4QAAOSwnFZXU-ny

It sits on top of the gearbox, towards the front. If the seals are leaking, then you will see a wet patch of brake/clutch fluid on the bell-housing. If you peel back the rubber bellows it should be dry underneath, rather than covered in fluid, so that's the "no-brainer" test.

I think what happens is the O-rings inside the cylinder grip the moving rod, rather than sliding over it and can get pulled out of their groove enough for fluid to leak out. By pumping the pedal a few times, the seal can/usually re-seat itself.. which is why it seemed to be mysteriously self-fixing last time.

But, if you see it's been leaking, it's time to change it. It's had its fun.. and it won't get better as more time goes by.

Ralf S.

 

[Ralf S.]

You beat me to it. Yes.. looks like the same type of cylinder that I dug up.

Valeo is pretty good at that price.. and we FF-er's gets an additional S4P 15% discount (see separate thread).


Ralf S.

 

[Davren]

The clutch and brake hydraulic systems share the same fluid reservoir, so any leak could be coming from either system.

The fluid take off pipe to the clutch slave cylinder is located higher in the reservoir than the take off to the brake cylinder. It's designed that way as a safety feature, so that excessive fluid loss will cause the clutch to stop working before the brakes stop working.

None of this explains why the clutch pedal went hard though.
.

 

[penguinpaul]

The clutch and brake hydraulic systems share the same fluid reservoir, so any leak could be coming from either system.

The fluid take off pipe to the clutch slave cylinder is located higher in the reservoir than the take off to the brake cylinder. It's designed that way as a safety feature, so that excessive fluid loss will cause the clutch to stop working before the brakes stop working.

None of this explains why the clutch pedal went hard though.
.

I think that was a bad description on my part! I didn't mean hard at all - I think it was just slow to return. It may have been a bit stiffer to depress, but I can't remember exactly.. I was struggling to find the car park at the time.

I'm grateful for the fact it loses the clutch first, but like you say, it could be the brake system.
I'm going to see if I can see any moisture around the clutch slave cylinder though, as this would be great if it is the culprit.

 

[penguinpaul]

Had a look - yes I have the external slave cylinder.. and even better, theres a lot of fluid under it!
Hadn't realised that we had a code for S4P, so that's even better! Arrived with DPD today.