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Derek, Can you describe the "clanging" noise a little better. From your description, it doesn't really sound like a rod knocking. Did the guy who diagnosed it as a rod bearing actually listen to it, or did he guess from your description. A bad connecting rod bearing will knock, i.e., sound like someone is hitting the engine with a hammer, and the knock will get worse under load. If its "clanging" like a bell, I'm not sure what that might be. One possible way to tell is to open the throttle just enough to keep the engine from dying and pulling the spark plug wires off one at a time. A rod knock will be significantly quieter when the associated cylinder is not firing. A bad rod bearing will also likely result in low oil pressure since a lot more oil than normal will be passing through the loose bearing, however, the most likely cause of a bad rod bearing is low oil pressure or loss of oil. Agree that in general repairing a rod knock requires pulling the crankshaft out of the engine, and having it reground for undersized bearings, not something you can do with the tractor sitting in the middle of a field. IF you're lucky, and IF its just starting to get loose, you MIGHT get by for a while with just replacing the bearing insert. If there's any roughness or anything more than surface scratches on the journal, just replacing the bearing won't hold up at all. Regardless, unless the journal is in good shape, not scratched, and not out of round by more than the allowable spec, you're going to have to have the crank re-ground. If you do attempt to replace a single bearing, you'll also need to measure the journal with a micrometer & see if it's been ground before so that you can order the right size bearing. You'll also need a good torque wrench to properly tighten the rod caps, plus all the normal mechanics tools. If I were in your position, particularly considering that you obviously have very little experience, I think I'd hire someone to come out to wherever the tractor is and do a real diagnosis before tearing into the engine. As pointed out below, you can do much more serious damage by running it with a bad bearing, including breaking a rod & throwing the end of it through the side of the engine, or seizing the engine from lack of lubrication to other bearings. Good luck, Keith
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