What causes a grabby clutch?
 

Brand new clutch plate, pressure plate, TO bearing and flywheel was resurfaced. I am finding it very hard to take off smoothly with this truck, getting some clutch grabbing/hopping when leaving from rest. What causes this? If this was an old clutch I would say hot spots on the flywheel and/or pressure plate, but it is all new. Will this go away as the clutch wears? I have about 300 miles on it so far. I have never had a clutch do this before.

Possibly need to bleed the hydraulic clutch?

-Wes

Where did you get the clutch and pressure plate from? There are alot of different style and designs of clutches that produce different performances and it can completely change how the truck drives.

Is there any sign of the slave or master cylinder leaking? Alot of times the extra stress placed on the master and slave when the clutch is nearing the end of the its life will kill seals and not provide enough pressure to work the clutch correctly, It may work, just ot how its supposed too.

Can be caused by, oil/grease on clutch or warped clutch disc or warped pressure plate or loose engine mounts or loose splines on clutch hub or worn universal joints or loose bellhousing bolts. And probably others.
because everything else is new I think I would look to the engine mounts.

grabby clutch
 

I had same problem , found out it was a .0020 shim i was told to put in to compensate for cut flywheel. Think it was making flywheel wobble and it only takes a few thou to make it chatter,removed and all was fine.Maybe your flywheel is not on flat to crank?

Had a heck of a time getting it bled properly, I thought once I did this would go away but it has not.

I got it from Advance, I am thinking that might be my problem, I did not spend enough on this.

Not that I can see. I don't have any fluid on the ground or on the slave or master cylinder. This is on a 460 so it is an external slave.

Good thought - I can check those tonite if I have time to put it up on the lift.

How does the pedal travel feel? Good and solid or spongy? does it grab close to the floor, or up high like it should? Can you feel it starting to grab and control it, or does it just go.

If the pedal feels good and all is working properly. I would suspect that its the clutch material. The manufacturer probably makes the material to be super grabby and very resilient to keep people from slipping the clutch and giving them warranty issues. This will be even more noticeable if your coming from the original clutch because ford wants the truck to be drivable and smooth of the lot.

My '88 F150 parts truck has the same problem, very grabby clutch, and very low and stiff pedal. Operated great, even tho it was pretty low.

It engages up high, pedal is firm, I am pretty sure I've got it all bled out. If I really think about what I am doing, rev the motor and slip the clutch quite a bit, I can keep it from doing it sometimes, but sometimes it doesn't make any difference, it does it anyway. But just driving normal like I am used to, it does it even on upshifts and downshifts. It makes the dash shake up and down.

May not be a good idea but we used to replace with NEW clutch parts as reman units can be slightly warped and not worth redoing. If the slave cyl is part of the throwout it could be leaking a little onto the disc. but not onto the ground..keep a close eye on your clutch fluid level.

Having said that.

Another issue is people would baby a chattering clutch trying to make it go smoothly.

well, that always makes them worse so we'd take them out for a run, with or without the customer, slip them till we could smell the clutch disk smoke and they'd smooth out as nice as can be.
ie, start out in 3rd gear a few times and really smoke 'em. I mean not enough to start a fire or cause damage.

Never really charged for that kind of clutch 'adjustment' and much easier than pulling everything apart again, and shouldn't really hurt anything.

Of course, all the other suggestions are great too.

Line up pins for the pressure plate, flywheel bottomed out to flywheel etc, bell house not square, did you grease the clutch disc splines a little?
but you say it kinda works nice sometimes? which would eliminate obvious structural misalignment.

Good luck.

Yes, I did this, as well as a light coating on the face of the TO bearing. Slave is external, it is not integrated like on a 300/302/351.

was it a stock replacement clutch disc and pressure plate?

From what you describe, it sounds like its clutch chatter. I was thinking that you were saying that when you were letting out the clutch, that it would get to a certain point then grab and either stall the engine or make the truck jump forward.

But it sounds more like your describing chatter(or what could be described as grabbing) as you slip the clutch to get the truck moving. Does that describe your problem better?

Yes.

Yes, this is the issue. I used to call it "chatter" as well but to some folks this implies some sort of noise, so I did not was not sure what to call it. Also I generally equate clutch chatter with a worn clutch that has become glazed, which is not the case here. Anyway this is probably just my bias creeping in, I agree it's clutch chatter.

I am probably gonna try this when I get it back from the muffler shop, it can't hurt since I am about to yank the trans and return the clutch to Advance anyway.