Frequently, there are posts about sticking foot clutches on the later SC and DC models. I rescued a foot clutch DC out of the junk yard and the clutch had sticking problems that continued to re-appear after setting for several weeks of time. Finally, I decided to split the tractor and look for the problem.
The problem was not obvious until I compared the flywheel to the cross section of the foot clutch in the photo. The area that I labeled "crud trap" was completely full of semi hard material and the horizontal drain holes were also plugged. The stiff crud in than area blended into the flywheel and was not obvious to causal observation. The crud would slightly bind against the OD of the clutch disc to where it would not release after setting awhile.
Note in the other picture that the hand clutch cannot trap material in this area. I have never had a hand clutch not release.
The "dry" crud was somewhat like clothes being spin-dried in an automatic washing machine. In my situation, I guess 60 years of spin-drying dirty oil is what fills the area with curd and created the sticking.
A dirty spline could also hold the clutch disc against the flywheel. However, the construction of the clutch disc center portion tends to compensate for a stuck spline and allow for some axial separation of the flywheel and clutch disc. Because the clutch runs in oil, I am at a loss as to how an oily interface between the flywheel and clutch disc could stick together. I cannot imagine "vacuum cups" forming at the interface and no one is suggesting that.
The problem was not obvious until I compared the flywheel to the cross section of the foot clutch in the photo. The area that I labeled "crud trap" was completely full of semi hard material and the horizontal drain holes were also plugged. The stiff crud in than area blended into the flywheel and was not obvious to causal observation. The crud would slightly bind against the OD of the clutch disc to where it would not release after setting awhile.
Note in the other picture that the hand clutch cannot trap material in this area. I have never had a hand clutch not release.
The "dry" crud was somewhat like clothes being spin-dried in an automatic washing machine. In my situation, I guess 60 years of spin-drying dirty oil is what fills the area with curd and created the sticking.
A dirty spline could also hold the clutch disc against the flywheel. However, the construction of the clutch disc center portion tends to compensate for a stuck spline and allow for some axial separation of the flywheel and clutch disc. Because the clutch runs in oil, I am at a loss as to how an oily interface between the flywheel and clutch disc could stick together. I cannot imagine "vacuum cups" forming at the interface and no one is suggesting that.
