Clutch "goes" when hot.

Can anyone help.

Noticed sometime ago that after a 25 - 30 minute fast motorway run, or a few laps of track my clutch started to lose effectiveness and wouldn't disengage the drive (not much fun coming in Redgate or coming up to a roundabout at the end of a slip road !). The weird thing is that after cooling down by driving at 40-50mph it comes back again and works fine. Its been to my local garage who are pretty good at such things and they bled it but it actually seems worse rather than better.

Its very odd n'est pas ? Is the fluid getting too hot ??

The turbo manifold runs very close to the clutch pipes, and on a hard session is quite prone to boiling the fluid. On the Europa cup models and A610, they lengthened the manifold tubes to raise the turbo to try and remedy the problem. The only other way is to remove the turbo and try and insulate the pipes using exhaust wrap (could also wrap the manifold tubes while your there, and fit metallic relflective sheet.

Thanks David. I'll try wrapping the pipes and manifold. I also wondered if putting competition spec (higher boiling point) fluid might help ?

Paul,

Just a thought - if it is boiling the fluid when did you last have it changed?

Brake / clutch fluid is hydrophilic (water loving) and with age the fluid 'goes off', even the slightest amount of moisture being absorbed will lower the boiling point considerably.

My car has Dot 5 fluid which can withstand much higher temperatures. (The cap on the reservoir says to use dot 3 or 4 which aren't as good) but you would need to refill and bleed the whole system which is a bit of a pro job!

Good point. Actually I have never changed the fluid and I've had the car 4+ years. So this may be exacerbating the problem. Also its been getting gradually worse, which again would point to this, although the recent bleed. Its also been suggested that the seals in the master cylinder maybe past their best so that when the cylinder gets hot and expands its not sealing properly.
So it looks like I need a combination of new seals, dot 5 fluid and exhaust wrap.... doesn't sound like a cheap job to me...

The master clutch cylinder is actually not very expensive (the slave is the bad one because of its location under the turbo) and new fluid shouldn't come to much.

Have a look at the shaft that connects from the clutch pedal, if its leaking badly then you'll see fluid weeping.

Also check in the 'V' of the engine (look down between the plenum chambers in front of the water pump) if the slave is leaking then you'll sometimes see fluid pooling here. If it is then get it changed quick - often when they pop they break the fork on the clutch mechanism and hence more cash!!!!!!!!

Are the brakes affected at all? Different circuit I know but they do share the same fluid.

Actually I think i got my master and slaves mixed up, because I think its the one under the turbo thats the problem due to the heat.
Am tempted just to try replacing with the dot 5 fluid first and see how I get on.... have already spent a fortune this year and still have a non working speedo to fix as well....
Brakes seem fine.

Thanks to all those that posted help here. Took all the advice, and changed fluid and new slave cylinder and wrapped it all it heat proof wrap... works a treat and no graunchy noises when trying to engage reverse now either

There is a Renault Advice Note that recognises this as a customer complaint and details a rectification.

If you wish I can email or post you a copy.

rgds,

Paul.