Fan Drive Pulley Woodruff Key

I have a TE-20 Ferguson tractor. The engine runs, but the pulley coming out of the crankshaft does not turn with the engine. I can turn it easily by hand using a wrench, but the pulley and the crankshaft do not appear to be connected together. The pulley does not seem to be running on the shaft, so I’m wondering, is there a connection inside the engine that can brake and stop the crankshaft from engaging the pulley?

The front pulley, crankshaft or fan drive pulley, is held in place by the crank nut but is connected to the crankshaft with a 1/4″ x 1″ woodruff key. I would check to see if the key is still in the crankshaft. You will probably have to remove the hood and radiator and then unbolt the front axle carrier in order to remove the front pulley. The “Crank Nut” is right hand thread bolt — you turn it to the left to remove it. You can verify this by looking at the notches or pawls for the crank pin. You can only turn the crank to the right or clockwise which has a tendency to tighten the crank nut. There is a possibility that the threads on either the crank nut or inside the crankshaft are stripped.

The crank nuts are relatively easy to find if you need to replace it and the female threads in the end of the crankshaft can usually be repaired with a “heli-coil”. You may have to exert some pull on the crank nut while you turn it clockwise in order to remove it if the threads are stripped. You can make a tool to do this by modifying a 6 point socket by drilling and tapping the sides of the socket for set screws that will grip the nut and allow you to exert some pull on the nut. When I did this I used set screws with points on the ends and drilled small impressions in the crank nut at the point where the set screws were located. I then used a “pickle fork” tool to exert a pull on the socket. You can also drill holes in the sides of the socket and then weld the socket to the crank nut. You’ll sacrifice a socket and the crank nut in the process but you should be able to get it out that way.