how to solve clutch shudder?

[TDR]

Just got on the road this year, my '66 Mustang, 200-6, 4-speed Dagenham. All works well, except the clutch will not engage smoothly. Instead, it shudders - shakes the whole car, in fact. I've gone so far as to yank the trans back out, and inspect everything. All is new, except the flywheel, which was refaced. Can't find anything wrong. Any ideas? Back when this car was my daily driver (early 70's), it had the same drivetrain except for the Dagenham (had a 3-speed then), and I don't remember the clutch shuddering like it does now. Anyone have experience with this? I sure would like to correct, as the condition is spoiling an otherwise sweet, little car.

 

[Anonymous]

Are you using the original type three fingered pressure plate?

 

[jahearne]

I read in a post somewhere on this forum where the flywheel was too thin from resurfacing; the thin flywheel warped from heat.

Good luck,

 

[66 Fastback]

Was the pilot bushing replaced? A little sole here can contribute. Also since it sounds like you replaced transmitssion and bellhousing? it could be that bellhousing is not aligned properly. The shop manual covers the method to check alignment. My old 3-speed always seemed to have some shuddering. Once I installed a T-5 with the lower gears, the shuddering went away.
Doug

 

[73GreenMachine]

What about the little bearing in the end of the crankshaft that supports the end of the gearbox input shaft? I left this out and it caused shuddering clutch and on occasions it would make shifting really difficult and also cause the gearbox to leak from that front seal. I will be installing one when I convert from the Toyota 4 speed to 5 speed gearbox.

 

[Anonymous]

Another thing that you could check is your clutch fork bracket if it's loose or bent it could cause your throw out bearing to be slightly cocked so that you're engaging your pressure plate fingers unevenly.

 

[Hot 6t Falcon]

Howdy,

The first cure for the shudders -'cause it is free if you do it yourself - is to tighten the "Z" bar between the frame and the block..

To be more clear... follow the clutch pedal rod coming through the firewall - it attaches to a lever that is welded to a round bar (this is the "Z" bar) that goes between the frame and the block. It then has another lever welded to it that has a rod bolted to it that goes back to the bell housing.

On the frame side of the Z bar there are two bolts that should be loosened (NOT removed), then pry the bracket toward the block, and the two bolts retightened. There is usually a greese zerk on the Z bar. pump it full.

Before you start, run your fingers around the ends of the z bar checking for cracks. Also inspect the welds of the two levers for cracking. There are bushings (or should I say - there are supposed to be bushings) on both ends inside the Z bar that may be in tough shape.

If the z bar is at all loose, it lets the clutch release fork in the bell housing "bounce" and then the clutch chatters.

Anyway see if this adjustment helps - best of all , it is a free adjustment if you're willing to get greasy.

Good Luck
Dennis S

 

[TDR]

Thanks one and all for your suggestions. I can't say that anything mentioned jumps right out at me, but it sure gives me some things to check. Everything (and I mean EVERYTHING) on this car has been rebuilt or replaced, but that doesn't necessarily mean it was done right. Since I was switching from a original 3-speed to the Dagenham, the clutch, pressure plate, and bell housing, were all unique for the Dag. However, each piece ended up coming from a different source. The clutch, pilot bushing, and throwout bearing all came from NPD, and I would like to think they are correct. I believe the clutch is a "three-fingered" unit. The bushings for the Z-bar are fresh, but it's definitely something to check. How about the taller gearing? The car has the stock rear end ratio, which is a 271(?). It's been so long since I looked it up, I forget. Got about an encyclopedia's worth of notes on this long, drawn-out resto, I'm sure it's written down in there somewhere. Anyway, thanks again for all the info, guys.

 

[Anonymous]

Another thought

The next time you pull your transmission take a look at the wear pattern on the three fingers of your pressure plate. If they are all not wearing equally that could be a indicator of your problem. I suspect that your pressure plate was probably a remanufacured one. I've found from my own experience that before you install one of these units you should always measure the height of the fingers to make sure they're all the same.