tbran
Guest
am assuming(IJ) you are talking about 71300399 countershaft belt set. These drive the shaft that drive the pump belt. Bottom pulley must be lined up perfect with top. No brgs loose, no shaft sliding inside brgs. Idler must be perfect using the special inertia_welded pulley n71178651 as it runs on the back of the MATCHED set of belts. Replaceing the bushing 71172846 and arm bushings 2-71171117's doesn't always assure the idler is true. Try running with one belt for a short while (this is kind of a last repsort we use) and watch belt. The way it streched will indicate which way idler is off...If only comes off when unloading, look for broken frame support. Final thing - ouch, gulp, a broke crankshaft will throw the belts forever 
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