AC 175D Front Axle Kingbolt

We have an AC175D with oscillating wide front axle pivoting on a steel rod hung on 2 trunnions under the frame of the tractor.  On one trunnion is a 3/8 Grade 8 kingbolt to keep the rod in place in the trunnion.  This bolt breaks at the end of the threads quite often, may last 1 month or 3 months or a year, but always breaks at the end of the threads of the bolt.  There are no grease fittings in the trunnions!  We do oil often but apparently not enough, as it does not prevent breakage.  I did try to drill 1/8 in hole in trunnion to install a fitting but there is a very hard bushing thru which I cannot drill with ordinary drills and hand tools.  Does anybody have a proven solution to this problem which will keep the rod in place?  This sort of wide front axle is common on many AC tractors.

They eventually went to the larger 1/2" bolt because of the failures with the 3/8" bolt being sheared off. This is due to too much rotational drag on the large pivot pin, especially with a loader. What you don't want is the pin to fall out. You can probably drill it out to 1/2" if there's enough meat there to work with. But if you weld the pin on the front with a new bolt in the rear it will never fail. Why will you ever need to remove that pin ?? You won't.

I'm sure they thought it was, but unfortunately who within the A-C company ever followed up on such a problem after they quit making the tractor ??  NO ONE did!!  I'm sure it was an improvement regardless. They had the same issue on the 7000 series and finally went to a snap ring on the rear of the shaft instead of a thru bolt. On the front of the pivot shaft they welded a 1/4" x 3" x 3" square plate to it. Then, they welded a piece of keystock to the axle frame up against the square plate. This kept the pivot shaft tied to the axle framework as far as turning, but by removing the snap ring at the rear, one could remove the pivot shaft. That was a good fix. I have done that on some maroon chassis tractors while still leaving the bolt in the rear and I have welded many other solid to the axle frame at the front, while leaving the bolt at the rear. Again I ask...….why would anyone ever want to remove that pivot shaft ???????????

Edited by DrAllis - 14 Nov 2021 at 12:08pm

November 12th 2021 till July 2022 is only 8 months by my math.