Ken,
For your serial number, you should not have a brake system. I posted the <10,000 PTO assy.
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Did the replacement crankshaft come from a K301AS with the same spec number as what you took out? If the spec number was different, the crankshaft maybe different. The necked down diameter the rotor and pulley assembly butts-up against maybe at a different location than what you had.
By shimming out your field coil assembly, you are forcing the front of the coil into the rotor. This will cause the engine to lock when the bolt is tightened.
Check your crankshaft to be sure it is not bent. If there is run-out on this shaft, this will also cause the rotor and pulley to contact the field assembly. Install the field assembly with no shims.. I agree with Ken, you should also check the field assembly to the crankshaft to be sure it is centered (preferably within .001” runout max, but there is no spec on these older blocks that I am aware of). Install the rotor and pulley assembly, spacer, and locking bolt with washer. If everything is centered, but still locking when tightened, you may need to shim out the rotor & pulley assembly using a thrust washer with the same ID & OD as what is on the pilot end which butts against the crankshaft.
I will also add, make sure the plate for the feild coil which bolts to the block is not bent or damaged from the crank seal. This plate should be flat and not come in contact with anything except for the block.
For your serial number, you should not have a brake system. I posted the <10,000 PTO assy.
Did the replacement crankshaft come from a K301AS with the same spec number as what you took out? If the spec number was different, the crankshaft maybe different. The necked down diameter the rotor and pulley assembly butts-up against maybe at a different location than what you had.
By shimming out your field coil assembly, you are forcing the front of the coil into the rotor. This will cause the engine to lock when the bolt is tightened.
Check your crankshaft to be sure it is not bent. If there is run-out on this shaft, this will also cause the rotor and pulley to contact the field assembly. Install the field assembly with no shims.. I agree with Ken, you should also check the field assembly to the crankshaft to be sure it is centered (preferably within .001” runout max, but there is no spec on these older blocks that I am aware of). Install the rotor and pulley assembly, spacer, and locking bolt with washer. If everything is centered, but still locking when tightened, you may need to shim out the rotor & pulley assembly using a thrust washer with the same ID & OD as what is on the pilot end which butts against the crankshaft.
I will also add, make sure the plate for the feild coil which bolts to the block is not bent or damaged from the crank seal. This plate should be flat and not come in contact with anything except for the block.
