Clutch heavier after biting point?

[Ross]

Hi guys

A quick Q... noticed this on a few cars I've driven and wonder if it can be considered normal:

If you press the clutch pedal, about half way down the clutch suddenly gets lighter and then stays light until the floor. It's smooth and consistent, but like it's in 2 stages. Bringing the clutch back up, it's the same in reverse, light until biting point, then the clutch pedal is heavier after biting point.

I've only driven it about 5 miles in recent months but it doesn't appear to be affecting it - it bites and holds 1.2bar of boost fine, and I've not really thought anything of it. I just don't remember it feeling like that on my 3B! It's a clutchnet carbon fibre & 3B flywheel combo.

Anyone have the same, or know if this is indicative of a problem? Perhaps it needs yet more bleeding?

[Rusty]

Could be the master cylinder push rod, the joint in the middle of the rod deforms and it bends, eventually snapping. Lots of ways of sorting it for less than the £120 for a new MC.

[Sonic]

The s2 is pretty consistent, but the clio feels the same. Heavier at the top, lighter at the bottom after the biting point.

[GazzaG60]

sounds like a bent master rod. mine was very similar.

[Christophski]

Mine is the other way round. Seems light with nothing behind it when yoiu first push it. Almost like the pedal has slack in it, then it goes heavy from biting point to the floor?????

[Fat Audi 80]

Mine feels "double" sprung. It feels like it takes up slack, then disengages the clutch. It been like that since, clutch, slave and master were all done at once.... (I assume it is meant to be like that.. )

Cheers,

Steve.

[mark_s2]

Ross - you MOT'd that car yet?

[GazzaG60]

christophski - yours sounds identical to mine. bent rod in master. the curve in the rod helps pull the pedal down. eventually it may fall on its own to halfway then be hard to push. its about to snap then.

buy a proper vag part.

[Ross]

Ross - you MOT'd that car yet?

I'm afraid not!! I've got to sort a squealing front-right wheel and then it's in... fingers crossed for the brake lines and then we'll get them sorted in the summer.

[mark_s2]

...and the baby? Any news?

[Ross]

He's stubborn! Won't come out despite lots of pre-labour signs and contractions... we're in to see the midwife in 2 days if she's still not had it, then it's induction and if it gets to Friday they'll get out the scalpel...

[Jamo]

It's your own fault Ross obviously he wants to be taken home in the Avant and it's not running

[Quattro Dan.]

I think the clutch pedal feel is due to the over centre spring on the clutch pedal, i have removed mine and the pedal feels consistent over the full travel. However running without the over centre pivot spring is not ideal.

[Dpicariello]

Don't worry, it's just a characteristic of a diaphragm spring. You get a fairly linear force v displacement graph up until a peak load when it tails off. Beyond the peak, the rate is less and therefore feels soft. You can feel it more when your clutch is worn as you are moving the release bearing more.

If it feels really soft then the you may be over stressing the diaphragm spring which could lead to a failure, by this point though the clutch would be sufficiently worn to slip.

If people have had this feeling with bent push rods etc. then it could equally be that. How many miles on your clutch and have you hammered it? Any details on the clutch? You stated that it's a carbon plate? Really??? In a n S2??? That must be a pig!

[Ross]

Don't worry, it's just a characteristic of a diaphragm spring. You get a fairly linear force v displacement graph up until a peak load when it tails off. Beyond the peak, the rate is less and therefore feels soft. You can feel it more when your clutch is worn as you are moving the release bearing more.

If it feels really soft then the you may be over stressing the diaphragm spring which could lead to a failure, by this point though the clutch would be sufficiently worn to slip.

If people have had this feeling with bent push rods etc. then it could equally be that. How many miles on your clutch and have you hammered it? Any details on the clutch? You stated that it's a carbon plate? Really??? In a n S2??? That must be a pig!

Fair to say the clutch has some use on it... only a few thousand miles which was mostly gentle with some hard 430hp sprints... however, it was clear when fitting it to the Avant it had taken some hard abuse - 7k starts or the like! All I can say was not when I was driving it didn't As a result, clutch probably half way through it's life now.

Not sure what it is, the ClutchNet "Fibre Carbon" is listed as a carbon/ceramic friction plate, can't remember 100% but i don't think it's the kevlar plate. Feels very good, similar to stock, progressive with only a slightly harder bite - fine in traffic etc.

What threw me is i just don't remember it being like this before the engine swap!