Bite point feels very high... suggestions??

[thenick]

Hi all,

I changed my master & slave cylinders a couple of weeks ago and have since noticed that my bite point has been getting very high, to the point that it now only just engages before the top... It has a new helix clutch, new fluid as well as the master and slaves so it can't be a failure of either of them I don't think. All I can think of is that the connection between the pedal and the cylinder needs to be screwed in a bit or it all needs re-bleeding..

Would this be a reasonable explanation or am I missing something obvious??

p.s I haven't actually had a chance to look properly yet so this is merely to help me look in the right place!

[mdotrutherford]

Still got some air in there I think Nick IMHO, besides it is the first and easiest task to do before having to dig deeper.

[nikman]

By 'high' do you mean you let the clutch pedal rise higher than usual before the clutch engages/'bites'? And if so, that you don't have to depress it as far as usual before it disengages and allows you to select/change a gear?

IF the answer to these questions is "Yes" then with the greatest respect possible I'd disagree with my good mate Ian who just reckoned it needs bleeding again!! Is there more than usual free play before the pedal meets resistance? If you pump the pedal several times before using it, do you notice any difference in where the 'bite' point is?

[thenick]

That's right, the pedal rises higher than normal before drive is engaged. I'm drawn away from the re-bleeding idea because the pedal is still notchy when it engages, it would be more spongy if there was air in the system right? After using it a lot in around town driving, the bite point doesn't move at all and there is pretty much no free play in the pedal at all - it is solid from the moment I put my foot on it. I think it's probably that the locking nut behind the pedal has come loose and the spindle sticking out of the master cylinder has wound its self further into the pedal than usual thereby moving the bite point... At least I hope it is! - So I will have a look tomorrow!

[nikman]

Yes, I agree although not familiar with the adjustment and lcoking nut behind the pedal as never had to go there with my car. But it does sound as though the hydraulic system is doing everything it should be in transmitting the pedal commands to the mechanical linkage. Nick.

[mdotrutherford]

You're both right of course gentlemen, :smiley for thinking before opening ones gob:
Alas my apologies, thought it would be an easy try anyway.

[Hut49]

I suspect that one or more of the relevant dimensions of either the slave or master cylinder, or both, are marginally different to the original ones you replaced (this could be true of the clutch plate too). The result being that the required distance from pivot points in the system to the points of furthest and nearest "throw" to create proper actuation of the clutch mechanism are less due to the new components than they were before. So it may not be a loose adjustment nut behind the pedal (unlikely) - but more likely it will be necessary to release and adjust it to restore the pedal/mechanism relationship. The fact that there was some apparent (probably minor) movement of the pedal position upwards, probably reflects some superficial bedding in of the clutch since the physical coordinates of the linkage should not have changed (and has been said, any air in the system would have moved the clutch biting point down rather than up).

[nikman]

Yet ANOTHER Nick on this one!!! But I'd say this suggestion of slightly different manufacturing tolerances and small wear factors of replaced parts are the most likely explanation so far...... But let us know what you find. Nick.

[thenick]

Hut49 said:

but more likely it will be necessary to release and adjust it to restore the pedal/mechanism relationship.

Sorry for being thick, but what exactly do you mean by this?