CL RC6 or RC8?

[mikekean]

I really cant see how you can boil fluid with a wet boiling point of 200 degrees when it's housed inside a plastic reservoir TBH.
Lines in the engine bay passing a manifold perhaps, master cylinder itself maybe, but not the reservoir.

I also cant see why moving the reservoir would help at all, because even if the plastic could sustain enough heat to boil the fluid, hot fluid expands, so its coming out of the lines, not down from the reservoir, so you'd never draw the boiled stuff into the system anyway.

The heat is compounding, if your brake fluid is already 50 degree's from ambient in the engine bay that only gives you a 150 degree window before it boils.

 

[alistairolsen]

True enough I guess, so the issue is still boiling at the calipers, but it's more likely because the fluid is already warm. I wonder how much movement of fluid there really is, it's a pretty low displacement system and when you bleed old cars you invariably get some dark manky fluid from the calipers followed by clean fluid in the lines, suggesting it doesnt circulate at all.

 

[Tony Hunter]

It's a well known fact, that tracked clios have trouble with the reservoir overflowing with the heat.
I've said nothing of boiling fluid, it just takes another problem out of the equation.

 

[alistairolsen]

I'm not disputing you @Tony Hunter , just trying to understand the problem as I have the same issue with the pedal going long.

 

[JB21]

It's a well known fact, that tracked clios have trouble with the reservoir overflowing with the heat.
I've said nothing of boiling fluid, it just takes another problem out of the equation. :smile:

Yep my res has pi$$ed its pants on a few occasions at track days in the summer months...

 

[JB21]

I'm not disputing you @Tony Hunter , just trying to understand the problem as I have the same issue with the pedal going long.

Its got to be aeration of the fluid at high temperatures surly, what are you using?

 

[alistairolsen]

CL RC5+ fronts, Ferodo DS2500 rears, OE rear disks, Brembo HC fronts, ATE fluid and goodridge hoses.
I'm going to swap out the fluid and see if that imporves things, but otherwise I'm looking at new front pads as mine are down to ~3mm.

 

[JB21]

CL RC5+ fronts, Ferodo DS2500 rears, OE rear disks, Brembo HC fronts, ATE fluid and goodridge hoses.
I'm going to swap out the fluid and see if that imporves things, but otherwise I'm looking at new front pads as mine are down to ~3mm.

Another occasion for ATE fluid and mushy pedal then, read quite a few now over various forums. I'm gonna try Motul RBF 600 as it's only £36 for 3 x 500ml of eBay and read it has lower compressibility over the 660 but has a similar wet boiling point.

 

[mikekean]

My res use to piss out all the time, just don't fill it to the max level anymore and haven't had an issue since. Must be expansion that causes it..

 

[Tony Hunter]

My res use to piss out all the time, just don't fill it to the max level anymore and haven't had an issue since. Must be expansion that causes it..

Yes, it couldn't be in a worse position, we have ours checked by the scrutineers, to make sure there is fluid up to the fill mark.

 

[Tony Hunter]

Have you removed fog lights and arch liners etc?