51 AR Clutch

On my 1951 John Deere AR, when I pull the clutch back to disengage it, it does not release. I can drive uphill, down hill, or on the flats with it disengaged.
What I have done: I have replaced all the friction plates, clutch driver, and even the pully assembly. It still makes no difference. I have determined that what is happening is that the pully has too much travel on the crank shaft. For trouble shooting, I have loosened the brake up and when I pull the clutch back it travels to far on the crank cuasing the outter friction plate to grip the driver and keep it engaged. If I loosen the clutch plates up there is not enough tension to engage the clutch. I have measured the backlash on the crank shaft and set it to .005 play. What am I missing here? Is something worn on the crankshaft or the bearing housings? I have also made this same comparissions on my other trators and none of them have this problem. Any help would be greatly appreciated. Thanks
Before I get the "buy a manual" answer, let me say I have them. I have alot of them. I have every manual that was produced for each of my 13 John Deere tractors and many more for all the implements that I also have. Half of my tractors have been torn down and rebuilt 100% from the ground up. Kind of an expensive hobby. I like to tell every one that they are "Green Harley Davidsons". Any help / ideas / advise would be grately appreciated. Thanks in advanced.

Sounds like you need to adjust the pulley brake. When properly adjusted the clutch lever won't be able to go back far enough to reengage the clutch.

Been there, done that. Dont make a different. The harder you pull the clutch lever back the harder you will activate the brake. The problem is that the harder you do all of that it pulls the pully further on the crank which in returens engages the outter friction plate on the clutch driver....Whetehr the brake is adjusted properly or not, when you pull the clutch lever it sould not pull the pully far enough to grip the outer clutch plate to the drive. Any more advise or ideas will be gratly appreciatted. I do thank you for your time and imput!!!

If you have replaces ALL the friction plates..including the one Behind the clutch driver and serviced and inspected the Sleeve/Dog-Bones, and drive-pin and it passed inspection....
The Clutch-Brake is what limits how far the clutch unit can travel after it releases..
If it travels too far, the clutch will start to Re-Engage...
Different models had differing "Stops" for this adjustment..I believe yours is adjusted by the clutch-brake adjustment..

Ron.

I saw this on a B.The bushing in the pulley was not driven all the way on.Thereby hanging up on radious of crankshaft when clutch was disengaged. I found fault by trying pulley off other tractor.

How far back onto the crankshaft is your clutch driver disk going ? I suspect the splines are worn and it is going back on too far. Another problem I just remembered is to make darn sure the parts you have are for an AR ! I think there is something different in there for that late of an AR like maybe the outer plate ? I ran into this once and forget exactly what it was ?