Project Super C, Rear Axle Woes
This is the tenth post in our ongoing series on Project Super C. We are chronicling the rehabilitation of our 1954 Farmall Super C tractor, which has taken up residence outside of the Farmers Business Network office. If you are new to this series, please start with the introduction to the project in our first post.
When we left off, we had overhauled the rear wheels. Now we’ll tear apart the rear axles in order to fix the leaky gaskets (seen below) and to overhaul the seals and bearings that are internal to the axle assembly.
To get the axles off, we first removed the rear wheels, and lowered the rear of the tractor down to rest on the ground.
Next we needed to remove the axle assemblies themselves. As can be seen in the pictures above, they are bolted to the side of the tractor. Additionally, as we discussed in an earlier post, the inside ends of the axles are socketed into large bull gears within the transmission case, which transfer power to the axles and thus to the rear wheels. To detach the axles we needed to open the transmission case and unbolt the axles from the bull gears. This brought us to a surprise, as can be seen in the picture below, which looks down into the transmission case:
As you can see, the left axle is bolted to the left bull gear as we expected. However, the right axle is attached to the right bull gear using a completely different system (shown in the zoomed picture below): there is a groove cut into the axle’s splines and a snap ring fits into the groove. This prevents the axle from pulling out of the bull gear.
Was our tractor originally built using two different axle retention designs? We don’t believe so. According to this book and to the Farmall parts catalogs, the bolt-based retaining system was still in use on the early examples of the Farmall 200 (the successor to the Super C), so our tractor should have been built with two bolted-on axles. This leads us to conclude that at some later point the right rear axle on our Super C was replaced, presumably as a result of damage.
After unbolting and unclipping the axles from the bull gears, we then unbolted and removed the entire axle assemblies:
This revealed the next surprise:
These are the splined sockets in the bull gears that the ends of the axles fit into. The outside ends of the splines are cracked and chipped on both the left and right bull gears. We don’t know whether this damage occurred before the tractor was retired, or whether this is the result of decades of carrying the weight of the tractor in the same position. Regardless, the only fix would be to replace the bull gears and since the splines are only damaged at their ends, we are going to wait and see if they cause any issues.
We moved on to taking apart the axle assemblies so that we could evaluate and rehabilitate their internal parts, which are depicted in the diagram below:
As you can see, each axle assembly contains two bearings and two oil seals, all of which the axle itself passes through. The bearings support the axle at both ends and allow it to rotate freely. The inner bearing is lubricated by oil from the transmission case, and the inner oil seal keeps that oil from escaping into the axle housing. The outer bearing is lubricated by grease, and the outer oil seal keeps that grease from seeping out.
You can see the splined end of the left axle and the inner bearing that supports it in the picture below:
With the inner bearing sitting flush, we used “finesse” to dislodge it:
The rest of the disassembly process was straightforward:
When we got the bearings out, we found them to be in good shape. We removed the old grease and sludge, cleaned up all of the parts, replaced all of the old oil seals, replaced the felt seals which sit outside of the outer oil seals, and installed new zerks (the old ones no longer worked) that enable greasing the outer bearings.
Finally, after packing new grease into the outside bearings, we were ready to reassemble and reattach the axles. In doing so, we installed new gaskets between the axle assemblies and transmission case, solving the original leak that started us on this journey.
After putting the wheels and rims back on, this long part of the project was done. We have now rehabilitated all four wheels and axles!
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