IndyIan
Veteran Member
I found this service bulletin in my searching and I thought it would be better to have here for those of us with these tractors. Tractors made after May 2011 should already have the upgraded axles and bearings.
I think it covers all the Bobcat, Cub cadet, McCormick, model numbers as well.
The main advantage of the upgraded case cover and axle is that it uses a 6309 outer bearing instead of a 6209. The 6309 bearing has 31 KN static load rating and the 6209 has a 21 KN, so it should last much longer before failing. This is "ball bearing 2" in the diagram also does all the axial positioning and loads, which is why they used a deep groove ball bearing, and not a roller, as there is no dual row spherical bearing made in the 6209 size. I don't think "bearing 1" does much for axial loads, and in my tractor, this bearing seemed fine, even though the outer 6209 bearing was destroyed.
Also in the 6309 size is a dual row spherical roller bearing, 21309 which has a static load rating of 127KN, and I believe still has enough axial load capacity to handle the very significant axial loads of the bevel gears, and the axial loads of the front tire. Also I think it should have a low enough axial play to keep the bevel gears meshing correctly as well. You should talk to an expert before trying a 21309, and also I believe not many/any 2012+ tractors have broken a 6309 bearing, so maybe this upgrade is unnecessary? A 21309 should last forever if it has the axial load capacity.
I think it covers all the Bobcat, Cub cadet, McCormick, model numbers as well.
The main advantage of the upgraded case cover and axle is that it uses a 6309 outer bearing instead of a 6209. The 6309 bearing has 31 KN static load rating and the 6209 has a 21 KN, so it should last much longer before failing. This is "ball bearing 2" in the diagram also does all the axial positioning and loads, which is why they used a deep groove ball bearing, and not a roller, as there is no dual row spherical bearing made in the 6209 size. I don't think "bearing 1" does much for axial loads, and in my tractor, this bearing seemed fine, even though the outer 6209 bearing was destroyed.
Also in the 6309 size is a dual row spherical roller bearing, 21309 which has a static load rating of 127KN, and I believe still has enough axial load capacity to handle the very significant axial loads of the bevel gears, and the axial loads of the front tire. Also I think it should have a low enough axial play to keep the bevel gears meshing correctly as well. You should talk to an expert before trying a 21309, and also I believe not many/any 2012+ tractors have broken a 6309 bearing, so maybe this upgrade is unnecessary? A 21309 should last forever if it has the axial load capacity.