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| The first and most important thing to do is find out why the sieve is coming apart. Having run multiple CaseIH machines for thousands of hours custom harvesting, we found that they rarely come apart without there being a reason beyond structural failure of the sieve (unless you mean the fins have started coming apart or off the wires--if thats the case they can be brazed back on).
Things to check:
1) Condition of the main frame rails inside the machine that hold the sieve in place. By this I mean the angle iron the sieve rests on as well as the larger rail above the sieve. On the larger rails above, crawl in there and check the welds around where the 5/8 bolts go through them. Also check the bolts and bushings at the front of the angle iron.
2) Condition of the rubber bushings that make the shaker work. Any small piece of rubber coming out or missing indicates an improper strain on that bushing and this indicates a bigger problem beyond only replacing the bushing.
2a) If replacing the bushings, the shaker must be in exactly the center of its back and forth stroke to tighten the bolt through the bushing. And there is a proper torque for that bolt (the 5/8" grade 8 bolt), but that value escapes me... If you are replacing the BIG bushing at the end of the crank arm off the hex drive shaft, the shaker must be either all the way forward or all the way back to tighten it.
3) Take those crank arms off the hex drive shaft to check for wear on the shaft and the pressed-in cam that fits over the shaft. If there is too much wear and space there it can cause jarring throughout the whole shaker system.
4) Finally and most importantly, underneath those two biggest bushing there's the 10-hr grease zerks for the stub shaft and needle bearings inside the main support for the front end of the shaker. There can be too much wear on that stub shaft where the bearings run back and forth. On a 2388, for less than $120, both shafts and all four needle bearings can be replaced. Don't worry about how much wear there is, just replace them. You can check for play before you take it apart by leaving the shaft in the bearings and taking the bolts out of the top and bottom of that arm and moving the arm up and down. The smallest amount of play around that stub shaft was the culprit for alot of problems we had. But we found that every 500 separator hours or so, those shafts were beginning to wear and that was the final answer to our extensive shaker system problems. At that point we spent the $120 without thinking twice and the results in the field made us wish we would've figured it out two years sooner. So for the money, don't worry if you can visually see wear or not on the shaft.
We used a long-toothed corn sieve on the top doing mainly wheat, and corn and soybeans as well. I'd get the one from the dealer rather than trying to save 6.25% on one part and risk getting one that may not fit quite perfectly. The shaker system is the most sensitive area of your combine, I don't recommend taking much risk with it mechanically. Another possible effect of the jarring of the system is fatigue or failure of parts of that little grain pan below the back end of the bed augers. This moves with the shaker, and the hard-to-get-to bracket underneath the pan is what can break. That's also the bracket that holds those fingers that stick out and poke you when you're working in there. You can do wheat and soybeans without those fingers if it ever comes to that, but they're important for high volume crops like corn. | |
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top sieve for caseih combine?
