Quote:
I was thinking (conjecture) that the overcenter spring helped the pedal to return to the resting height. You're saying it helps in the effort to depress the clutch?
Then what returns the pedal to its resting position?
Josh gives a pretty good description. To that I'll add, just remember why it's called an "overcenter" arrangement. At the center of the geometry, the spring essentially does nothing (except wear the shaft with excess radial pressure). Below a certain point, it helps push the clutch down. Above a certain point, it helps pull the pedal all the way up.Then what returns the pedal to its resting position?
The problem is this: when you let up on the pedal, it isn't quite getting up as far as the center point, so the spring can't go "overcenter" to change its operating mode. As soon as you pull up on the pedal with your toe, it suddenly bangs the rest of the way up, right?
If you slightly lengthen the adjustment rod that contacts the clutch fork, all will be well. As you do so, your clutch engagement position will rise a tiny bit higher off the floor. But you'll be surprised at what a small difference it requires... keep lengthening a turn or two at a time, until suddenly when you try the pedal you feel that it wants to return. Then lengthen it one more turn for good measure, so it returns solidly.
It can feel like a new car again.
Oh, and if you wonder why it's changing its adjustment, or if you adjust and it helps for a little while but then pulls the same trick... look at the torque shaft (sometimes called Z-bar) carefully to see if it's failing. I've had to weld reinforcements on a couple of those. After years and years, the arms literally twist off the tube. (Somewhere I've got 35mm photos I could scan, but when you look closely, it's pretty obvious.)
- Erik