78 FJ40 Clutch release fork - adjustment? (1 Viewer)

[EricATX]

I am reading the following in the FSM and I don't understand what is meant by "release fork tip play"

"I have already adjusted the clutch pedal and now it says "Adjust the play at the release fork tip by loosening the lock nut, then either rotating the pushrod as the pushrod nut is held, or rotating the pushrod nut, as applicable."

I can see that I need 3/4 mm of play for the release fork. But where do I make that measurement?

 

[73FJ40]

I believe the play is between the release fork tip (while being held so that the throw out bearing is touching the pressure plate fingers) and the face of the push rod nut (with a fully retracted push rod) that bears against the the fork tip. You remove the spring to allow the fork to move freely during this adjustment. The result is that the push rod will have to move the

This 4.0 to 5.0 mm play ensures that the throw out bearing isn't sitting on the fingers of the pressure plate while the clutch pedal is fully released, and the slave cylinder is fully retracted.

 

[EricATX]

So remove the spring and wiggle the fork. And the wiggle should be the 4 or 5mm of play?

 

[73FJ40]

That's my understanding.

 

[EricATX]

I have a question about how the fork should feel. Let's say I move it to the left and it reaches the end point. Should I be able to push on it like the piston would and feel it engage. Because when I do move it to the left there is no amount of manual pressure that I can put on it to get it to keep moving to the left. Is that ok? is the piston really that strong?

 

[73FJ40]

You would need to be inordinately strong to compress the clutch plate fingers by pushing on the release fork by hand.

Lever theory. If you look at the clutch pedal arrangement, you can see the clutch master cylinder pin (2) is very close to the fulcrum, which is where the clutch pedal arm pivots (concentric with the bushing, (4). If the pin (2) is X distance from the fulcrum, and the clutch pedal lets say is 7X distance from the fulcrum, then 10 lbs of force on the pedal produces 70 lbs of force on the master cylinder.

If the master cylinder I.D. is the same as the slave cylinder I.D., then the slave cylinder output force is the same 70 lbs as the master cylinder.

If you think it takes more or less force on the clutch pedal, then adjust the math. If you think the 6X the distance from the fulcrum, then 10 lbs = 60 lbs of force on the release fork.

Here's an illustration of the clutch pedal.

 

[EricATX]

Thanks.

 

[EricATX]

Thanks again for the help. I had someone help me bleed the line and it is good to go.

 

[EricATX]

Just to close out this thread. I originally did the adjustment of the slave cylinder to have the 4mm "wiggle". After using the truck for a couple of weeks it started having trouble shifting into reverse. Took a close look at the slave cylinder setup. Turns out that the nut on the end of the rod that pushes on the fork had settled into the depression on the end of the fork. The result being it was not pushing the fork as far as it was when I first installed it. I removed the spring, adjusted the nut to be just barely contacting the fork. Moved the lock nut into place and it has been working perfectly since.

 

[NYccruzr1]

So what your saying is ditch the 4mm, and just adjust slightly off of the fork?? I just replaced the clutch on my 60 and it’s super tight.

 

[EricATX]

So what your saying is ditch the 4mm, and just adjust slightly off of the fork?? I just replaced the clutch on my 60 and it’s super tight.

Yes

 

[James Madigan]

Used a 14" bar to push back the fork so i could slip the slave rod in.