Clutch engagement point at the very end of pedal travel - LotusTalk - The Lotus Cars Community
 
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post #1 of 5 (permalink) Old 09-01-2017, 07:11 AM Thread Starter
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Clutch engagement point at the very end of pedal travel

Hi All,

I've had my engine and transmission rebuilt on my '07 Elise, since I wore them out with lots of tracking. As part of the rebuild, my mechanic installed stronger clutch springs, so it takes much more pedal effort to disengage the clutch. He's also bled the clutch twice.

Due to all the changes, my clutch engagement point is very strange. When I need to disengage the clutch, I have to push the pedal all the way to the floorboard, and even then, I think it's partially engaged because I have a little bit of difficulty getting the car out of gear, I have to fight a little bit against the transmission. When I'm in first gear and trying to get moving, the issue is the opposite, I have to let the clutch out almost all the way to the end of pedal travel before it starts engaging, and then it goes from 0% to 100% almost immediately, leading to some jerky driving. Shifting from gear to gear, it's a combination of the two, I have to get it all the way to the floor to disengage, then let it out almost all the way to engage.

I'm at a loss as to what's causing this, because it's inconsistent with air in the system. The master or slave cylinders don't seem to leak, since I can press the clutch in for quite a while and it doesn't seem to re-engage as it would with leaky pistons.

Last edited by marcinr; 09-01-2017 at 09:40 AM. Reason: Cleared up my vague description
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post #2 of 5 (permalink) Old 09-01-2017, 09:33 AM
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what year is your car?

Some of the cars 2008+ (the cars with launch control), I think, had a delay valve "damper" in the clutch hydraulics. Which could be delaying the release of the pressure plate as you release the pedal. That could make the bite point higher. Some people bypass that delay valve.

What brand is the clutch and especially the pressure plate? The pressure plate springs could be more digressive (non-linear over center springs), making it feel non-linear. It could also be that the flywheel was machined, and now has an incorrect step height for the friction surface, which could change the clamp load and the adjustment of the clutch hydraulics, making the throw less than required to fully release the clutch.

Otherwise I suppose it could be fluid going past the master/slave cylinder piston seals reducing the piston effectiveness, reducing throw and slowing release.

Travis
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post #3 of 5 (permalink) Old 09-01-2017, 09:40 AM Thread Starter
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Thanks. Mine is a 2007, so maybe it doesn't have the damper. I'll find out what parts he used.
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post #4 of 5 (permalink) Old 09-01-2017, 11:23 AM
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I am suspecting something with the 'upgraded' parts

try this:

under light power in a higher gear, slowly depress the clutch till you get it to slip

where is it?
If it is up high then I suspect that the difficulty getting into gear is something along the lines of what VG mentioned, or perhaps a poorly fitting clutch disk/shaft causing drag on the clutch plate and difficulty getting into gear

IF it is down low then well, I dunno, might be two things going on

I have had hydraulic clutches act oddly when there is too much slop in the system, the slave rod would back up and you would have to hit the clutch twice after driving for a while, but then it would be fine after that until it backed up again. Took me a while to figure that out[I don't think that can happen in this system BTW]
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post #5 of 5 (permalink) Old 11-14-2017, 09:31 AM Thread Starter
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Mystery solved. One of the clutch dampener springs shattered, and pieces of it were wedged in around the bearing and fork. It finally gave up completely and seized on me during a track day.
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