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The mkiv Supra Owners Club

Clutch Pedal Movement/Adjustment


dani_r

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I did a straightliners event here in the Isle of Man last weekend, and although the car ran really well, the day after, my clutch pedal felt totally different.

 

I have an NA-TT with an RPS Street Max Clutch. It's only a few months old and when I picked up the car with the new clutch the pedal was totally stiff all the way to the floor, with the biting point pretty much at the floor.

 

Over time the biting point moved up as was to be expected, but the pedal remained stiff all the way, with only a slight bit of slack in the pedal.

 

After the straightliners event there is now slack in the pedal of a few inches then you get the stiffness in the pedal, and the biting point is right at the floor again. Can anyone suggest what's happened here? I imagine that if I had worn the clutch, that the biting point would have infact moved UP and not down, and would not account for the slack in the pedal.

 

I have spoken to someone about this, and they suggested that there is an air bubble in the system from the hot temps achieved at straightliners and that I should just bleed the system. Does this sound right?

 

Thanks, and sorry for the drawn out thread, I just wanted to explain as best as possible the situation.

 

Dan :)

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Well, if that's what HAS happened, and I am only making a measured guess, then yes, and if it's got hot enough to cook the diaphragm the flywheel may not be too happy either. How many spirited starts did you make? Drag racing is a transmission killer, where as I buy tyres, brakes and Rose joints, you lot buy clutches, flywheels, gearboxes and diffs :) We all spend a fortune, going straight, or around the corners.

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Well, if that's what HAS happened, and I am only making a measured guess, then yes, and if it's got hot enough to cook the diaphragm the flywheel may not be too happy either. How many spirited starts did you make? Drag racing is a transmission killer, where as I buy tyres, brakes and Rose joints, you lot buy clutches, flywheels, gearboxes and diffs :) We all spend a fortune, going straight, or around the corners.

 

I made quite a few runs to be honest. This is rubbish. It appears I got carried away! The annoying thing is that this clutch has only been on a few months! It still works totally fine, it still pulls well, it's just slackened off.

 

I guess the only way to find out what's happened is to get the gearbox off then? If so, what am I looking for?

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Try bleeding it after cleaning the master and slave cylinders (stripping them fully to clean them properly), fit new seal kits if the seals look bad.

 

I actually refurbed my master cyliner earlier in the year with new seals etc, should it pull it apart again? I didn't do the slave, so will give that a whirl.

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Err, the fluid is low? :) Try bleeding it through again, and see what happens. If bleeding restores normal operation check for a weep behind the slave and master cylinder boots. Reseal the slave if the bore is 100%, if the master is leaking after re sealing, renew it.

 

Top man :thumbs: Cheers Chris.

 

I'll get stuck into that and let you know. I've ordered a new slave cylinder seal kit ready for the weekend anyway. :)

 

Dan

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I think this is only an issue in LHD cars, RHD ones do not, as far as I can remeber, have this set up. Good home repair though!

 

 

Your lucky if that is the case. This seems a pretty common defect in the US cars.

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I think this is only an issue in LHD cars, RHD ones do not, as far as I can remeber, have this set up. Good home repair though!

 

How come this would only be a LHD problem Chris? Aren't the cars made pretty much the same way, just on the opposite side?

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How come this would only be a LHD problem Chris? Aren't the cars made pretty much the same way, just on the opposite side?

 

I was thinking the same thing.

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