Join Date: Jun 2006
Location: Hillsboro Oregon
Mentioned: 2 Post(s)
Quoted: 230 Post(s)
Your dealer should have the alignment tool, and maybe will let you borrow it if you do business with them, or maybe would rent it to you.
The slow down kit was a remedy for a speed up kit the 2188s had. Possibly the last 1688 had them to, but your 1680 should be the same speed as the slow kit, or as it should be stated, the same speed as normal.
The plates would break because someone either did not tighten the bolts well enough, or they used the stock bolts that are called for in the book. I looked at the bolt length and position in the arm, and really did not like it. So,....I use USA made grade 8 bolts that the shoulder goes all the way through both the cast part and the plate. The threads stick out a bit further and a cut off wheel should be used to cut them off, but the issue that I see is when you have a bolt in that position with the shoulder in part of it and threads in the other half, it is a problem looking for a place to happen.
There is a needle bearing setup on the pivot pins of the pitman arm. Those pins and bearings are replaceable and relubricable. 2-3 pumps each morning should suffice, no matter what the book says about them being 50 or 100 hour zerks. IMO.
When you replace the hex shaft, there is a 3rd bearing in the center of the shaft. That bearing holder has slotted holes. When you install the new bearing, leave the bolts loose until you have the shaft installed. Then tighten the bolts, holding the bearing in a neutral position. When the combine leaves the line, it has not had a load on the superstructure yet. Once a few heavy loads are hauled around and a few bumps hit, the superstructure will "settle" or shift slightly to it's life long places. Usually this shift places a bind on that bearing, which contributes some to the early failure of the shaft and cams.