5050 Thrust on Crankshaft

Is anyone here familiar with the add on attachment that went on the front part of the crankshaft on a 5050 to solve the thrust problem with the crankshaft?

Are you sure wasn't a 6060,6070,6080. I have a bearing on the front of the crank of my 6060. 4300 ser no I think. Factory add on after I had if for 6 months or a year. Neighbor had a 6080 that needed a new crank. He already had 5000 or so hrs. His was knocking bad. Factory put new crank and the bearing in his. I just grease bearing once a year. Seems to still be good. Vic

You might be right a fellow that worked at an AC dealership was telling me about it he may have been
confused on the Model.

It was definitely the 6060,6070, and 6080. I don't recall any problem, or kit for the 5050.- Although, now that you ask- I think it was the same basic design.- A hand operated dry clutch you had to disengage, then grind in the PTO gearshift, then engage clutch.

We had a 6060 for over 4000 hours. We got rid of it as the Fiat drive train scared us. And I hated that PTO system. If we had gotten a 6080, maybe we would have kept it.

What would the 6080 have offered to make you "keep it"? They where pretty much the same tractor. Maybe a bit heavier in some places, with a two peed PTO, and a bit more horsepower, but still a Fiat drivetrain.
The front mounted thrust bearings came about as a "fix" for the weaker thrust flanges in the AC engines used in the series, which would not stand up to the increased forces of the two stage clutch. The Fiat engines supplied with the tractors built and marketed by Fiat had much heavier flanges, and to this day do not require the front mounted bearings.

I had a 6140 that had the same issues as the 6060 and 6080 tractors, or at least a very similar problem.

The 6140 did not have true "thrust bearings" to keep the crankshaft in place. They had what I would call "shims" on the crankshaft lobes that they called thrust bearings. These were to keep the crank from floating forward and backwards. They might have worked except that if the pto hand clutch lever was pulled to the "disengage" position, the clutch springs put pressure on the shims and wore against the shims and the engine block. This then allowed for more float. The manual and the sticker right by the pto clutch lever warned that you should have the pto lever kept in the "on' position and the splined lever disengaged when not using the pto. However many people ignored the manual and the sticker and this wore out the shims and did damage to the blocks. Had AC put true tapered roller bearings at each end of the crank like a real thrust bearing should be, this would have never been an issue at all.

I know they made a big "bra" looking contraption for the 6080 to eliminate the problem but, I don't think anything was ever made for the 6060 or the 6140. The bra bolted on the front of the crank and kept it from floating. I imagine this would add a bit of work to doing anything on the front of the block, like changing belts etc.

I had made a bearing and bearing support to bolt on in front of the crank for mine to eliminate the float. It worked but I sold the tractor as I could see this being a problem down the road.

I don't know if the problem I had was the same ion the bigger machines but, if they used shims instead of thrust bearings, this would be a problem right from the design stage.

The 6060, 6070, and 6080 used the same basic engine and drivetrain. They had the same problem, and the same fix. I worked at the local AC dealer 72'-84', and was tasked with putting the external front thrust bearing kits on tractors we had out. One 6080 was used hard, and abused as you describe, before the fix, and I put a new block in that one. I got tired of stumbling around that old block after months, got the bosses OK, and scrapped it. Within a week the AC area service rep. was in looking for it, and or wanting measurements. Nice work guys! Nobody told me. But AC was about done for then anyhow.

"Classic view" has you replying to "Traditional Farmer", with a question that appears to be for me. Three significant differences might have influenced me to keep a 6080, and not the 6060.

1. 12 speed trans. instead of 8. Several working speeds instead of only two speeds we used.

2. 18.4x34 tires and cast iron wheels. Much more appropriate for the tractor. We put bigger wheels/tires on the 6060 to harness the power.

3. A drive train designed for 80 some HP rather than 60 some HP.

As I understood it, the 6070 was to answer some of those shortcomings in the 6060- 12 speed. trans, and 16.9x34 tires as an option.