Need some non-SC Ford clutch help

Mercutio

SCCoA Member
Some of you know about my 57 Thunderbird project. If not: I have a 57 Thunderbird that now has a 4.6 DOHC and T45 in it. The project is close to completion--the engine runs, and I've even driven the car with the new drivetrain, but the clutch setup is giving us fits. We've used the original 57 clutch pedal assembly, aftermarket JMC hydraulic setup and what we think is the factory clutch from a 96-98 Mustang. There are two problems that are probably related. First problem: there's almost know throw to the clutch pedal. I can't see it hitting anything, but it has maybe two inches of total travel. I drove the car on the factory engine & trans combo, so that's not a symptom of the stock design. Second problem: good God is the clutch stiff. It's pretty much an on/off switch. It takes all the strength I have to push it in, and I'm just not strong enough to let it out slowly--when I ease up on it a tiny bit, it just comes out all the way. This is the last major hurdle to the car's completion, so any help you guys can offer me on hydraulic clutches in general would be awesome.
 
My guess is the original clutch pedal pivot point was setup for a fairly easy going clutch and a cable operated lever which had in it's travel some sort of pulley setup thus easing effort. The on off comes from you loosing fine muscle control after pressing so hard and the pressure plate getting past it's initial point.

Master cylinder size will impact effort. A larger master cylinder will require more effort, but move more fluid. A smaller one will move less fluid but be easier to push.

When you say no throw to the pedal, I assume you mean the total distance you travel is pretty low. Does the clutch disengage fully when you press the pedal in? Are you sure the pressure plate springs are not pushed up against the throwout bearing partially disengaging the clutch?
 
When you say no throw to the pedal, I assume you mean the total distance you travel is pretty low.

Correct.

Does the clutch disengage fully when you press the pedal in?

Sure feels that way. The car doesn't move or try to stall with the clutch pedal pressed in.

Are you sure the pressure plate springs are not pushed up against the throwout bearing partially disengaging the clutch?

No, I'm not sure of that. It's something to check out.
 
Sounds like you need to move the master cylinder actuator rod closer to the pivot point of the clutch pedal....that would give you move leverage and more pedal movement for a given amount of master cylinder compression......Dan
 
Sounds like you need to move the master cylinder actuator rod closer to the pivot point of the clutch pedal....that would give you move leverage and more pedal movement for a given amount of master cylinder compression......Dan

Yes. Cylinder size of the master and slave is carefully balanced with the leverage applied by the pedal (distance from pedal pivot to slave arm connection) to arrive at good pedal feel and travel. It will probably be easiest to adjust pin height on the pedal, but if that is not practical you can also alter the cylinder size of the master or slave cylinder to achieve the same result. I am currently working on a T56 conversion on an SC and we had McLeod build a custom cylinder for us to match up components.
 
Definitely a hydraulic issue. Ive retrofitted a bunch of cars with hydraulic setups back in the day and never ran into this issue. Im thinking it has less to do with the size but location of the master.
 
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