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Discussion Starter #1
My standing pedal hydraulic clutch has an extremely quick engagement very near the floor, completely unlike any other standing pedal car I've driven. The clutch engages and releases completely, but it engages so quickly it is very hard to drive.

The clutch slave cylinder is new and replacement made no difference.

Anyone have any thoughts on what the problem might be?
 

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There is a threaded adjustment in the pushrod connecting the pedal to the clutch master. Adjusting that rod should make the clutch release at a different point in the pedal's travel. That wouldn't change how quickly the clutch engages/disengages; just where in the pedal travel release happens.
 

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Wouldn't shortening the rod, lower the pedal in the car and cause it to release sooner? Is the pedal in the same place as the previous slave cylinder? Wear on the clutch components ie pressure plate, can cause some issues as well. Good luck
 

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69s originally came with an adjustable pushrod for the slave cylinder to TO bearing fork. This was phased out, replaced by the fixed-length rod and ball end. Does your car still have that? If so you might replace that short ball/pushrod with the now-standard later style or at least make it the same length. Otherwise, I'd think your clutch disk might be near its minimum limit?

Floor pedal hydraulics to me are more suddenly in/out than hanging pedal, but if you've had better experience with others, then this one doesn't seem right.

Andrew
 

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Discussion Starter #6
69s originally came with an adjustable pushrod for the slave cylinder to TO bearing fork. This was phased out, replaced by the fixed-length rod and ball end. Does your car still have that? If so you might replace that short ball/pushrod with the now-standard later style or at least make it the same length. Otherwise, I'd think your clutch disk might be near its minimum limit?

Floor pedal hydraulics to me are more suddenly in/out than hanging pedal, but if you've had better experience with others, then this one doesn't seem right.

Andrew
No, it's definitely not right and very different from my '69 GTV. It sounds like I might get similar results with a longer slave pushrod or shortening the master cylinder pushrod. Although, I installed a new slave cylinder with a longer pushrod than what was in it and it didn't make any difference......

Does anyone know the proper length for the slave pushrod?
 

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Whatever the ones available are now, but I don't have one handy. The nonadjustable superseded the adjustable, even on 69s.
Changing the MC pushrod only moves the pedal angle, doesn't change anything in the MC itself of course. One problem I've had is corrosion in the pedal box pivot bushings, makes "going over the top" much more sudden. Kind of a reach, but other than a worn disk and/or pressure plate fingers, I don't have another idea.

Andrew
 

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Discussion Starter #8
Whatever the ones available are now, but I don't have one handy. The nonadjustable superseded the adjustable, even on 69s.
Changing the MC pushrod only moves the pedal angle, doesn't change anything in the MC itself of course. One problem I've had is corrosion in the pedal box pivot bushings, makes "going over the top" much more sudden. Kind of a reach, but other than a worn disk and/or pressure plate fingers, I don't have another idea.

Andrew
That makes sense. Thanks!
 

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Maybe post up a photo of the linkage (pedal to master). Downstream from master there isnt anything I can imagine, other than the clutch disk itself, that would have said effect.
 

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If the disk is very thin and/or the diaphragm fingers flattened out or worn thin, it changes the geometry and clutch feel and engagement is different; you don't get an overcenter feel, just a steady mushy feel.
 

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My standing pedal hydraulic clutch has an extremely quick engagement very near the floor
When you said "very near the floor", what exactly did you mean? At the top of the pedal's travel or at the end (e.g., when it's near the firewall)?

if it doesn't release until the pedal almost reaches the firewall (e.g., at the end of its travel), then lengthening the rod - not shortening it - would make it release earlier. Sorry, I seem to have gotten that wrong in my earlier posts (since corrected or deleted).

That would also cause the pedal to return more toward the fully released position, right?
Again, what does "the fully released position" mean? With the pedal pad closest to the driver / fully rearward? Are you saying that the clutch pedal doesn't come back as far as the brake pedal does?

If that's the case, then again, lengthening the rod would push the pedal's top pad farther backward.

Andrew said:
If the disk is very thin and/or the diaphragm fingers flattened out or worn thin, it changes the geometry and clutch feel and engagement is different
Of course, as Andrew suggests, it could also be something internal to the bellhousing and the pushrod may be the correct length. How old are the disk and pressure plate?
 

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Could this be a very low mileage car? The 69s had a poorly engineered pressure plate that wore rapidly at the throw out bearing friction point.
They were all replaced under warranty because of problems like this.
 

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The adjusting slave cyl have the same travel as the non adjustable ones. The start length should be the same on both as the only travel that the slave has is from the delivery amount that the master cyl gives it. Sounds like your pressure plate and or the disc and t/o bearing are worn. The only fix for that is replacement of the clutch components. The rod adjustment will change the release as it measures from the floor. The higher pedal the higher release, the lower the pedal the sooner release. Hope this helps and good luck.
 

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Did you replace the rubber line to the slave cylinder?

When they start swelling up on the inside. It will give you the problem you describe.
 

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Discussion Starter #15
I mean that engagement/disengagement occurs with the pedal very near the floor/firewall.

When the pedal is fully released (i.e., my foot is not on it), the clutch pedal doesn't return all the back (away from the firewall) to the stop.

The clutch slave, throwout bearing and flexible line are new. The master cylinder is of unknown age.

Reading between the lines in all the posts, it sounds like adjusting the master cylinder rod may result in moving the clutch pedal away from the firewall while at rest and also the engagement point?

When you said "very near the floor", what exactly did you mean? At the top of the pedal's travel or at the end (e.g., when it's near the firewall)?

if it doesn't release until the pedal almost reaches the firewall (e.g., at the end of its travel), then lengthening the rod - not shortening it - would make it release earlier. Sorry, I seem to have gotten that wrong in my earlier posts (since corrected or deleted).



Again, what does "the fully released position" mean? With the pedal pad closest to the driver / fully rearward? Are you saying that the clutch pedal doesn't come back as far as the brake pedal does?

If that's the case, then again, lengthening the rod would push the pedal's top pad farther backward.



Of course, as Andrew suggests, it could also be something internal to the bellhousing and the pushrod may be the correct length. How old are the disk and pressure plate?
 

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it sounds like adjusting the master cylinder rod may result in moving the clutch pedal away from the firewall while at rest and also the engagement point?
Yes, I'd start by lengthening the rod, perhaps enough to get the clutch pedal to come even with the brake pedal when at rest. The engage/disengage point should move up too.
 

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i think thats the only adjustment you can make -master push rod---unless you want to move the master closer to the front of the car..........
 

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extending the pusher in the slave wont do anything for pedal position as near as I can tell. I suppose you could machine up a new pusher, longer, which would push the slave plunger backwards, but the slave piston will have to displace the same length to release the throwout. But I dont think that will change the release point. But I'm far from expert in this.
 
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