Then 841 is the model number, which means that is an 801 series tractor, not an 800 series. The 801's were just a little later than the hundred series and had a few minor improvements. An 841 would have had the 172 ci engine, 4 speed transmission, non-live (trans driven) PTO and 3 point lift when it left the factory.
70636 would be the serial number, which would make it a 1959 841 tractor.
I believe the front axle for the 801 series is still pretty much the same as the 800 series. Here's a link to the parts page for the 841 front axle and steering:Front Axle & Steering
And here's the parts drawing for the front wheel and hub assembly including the bearings:Front wheel and hub
u[date: fixed the first link above. This post was edited by Sean in PA at 13:59:28 05/21/14.