Front axles on powermax models

[Nigel 0]

Hello, can someone explain how the front axles evolved and on what models they were strengthened. I understand there was an early and late version of the 9020 model. How did these differ from the 4041 and the 4040. Is it possible to upgrade a 4041 to match the late 9020 specification? regards to all Nigel

[D-17_Dave 12]

Welcome to the club Nigel. The evolution of these tractors varies between the Simplicity models and their Allis-Chalmers counterparts. The 616 and 4040 were the first models followed by the 4041 and 620 respectively. The bigest differances were the addition of a 2 spool lift valve and a heavier rear axle assembly. While AC continued with the 620 model Simplicity dropped the 4041 and went with the early 9020. There was basicly no change other than the model number at that time. When AC went to the 720, Simplicity followed with the late model 9020. There are a few minor changes in the electrical wireing/safty interlock systems. But the biggest change was the upgrade to the heavy front end on the late models of both series. The heavy front end is basicly a heavier vertical spindle with a larger cap where the tie rods connect. You can swap out the complete front axle for the upgrade. While it's the more desirible feature, it's really not neccessary unless your useing a front end loader. IMO

[Roy 0]

As one engineer to another, welcome Nigel. :)

[Guest]

Allow me to correct D-17 Dave, " heavier rear axle assembly". He meant to say, heavier FRONT axle assembly.

[Ronald Hribar 126]

I do think Dave meant rear axle . I heard they changed both front and rear.

[JP 0]

Well, In a true assembly operation, There was a direct correlation of the Allis to Simplicity in regard to the powertrain. The progression as I've seen it was; 616/4040. then 620/4041, then 'early' 720/9020 (as Dave mentioned, the decal change), Then the 'late' 720/9020. As far as I have noticed, The rear axle change was from the 616 to 620/720. The front seemed to have three versions, 616, then 620 to early 720 then late 720. The differences to me were (looking at the top of the spindle), Little nut, Big nut, Hockey puck. (LOL) The design was similar in the first two (two keys) with the 'Hockey puck' being more 'Automotive' with tapered shaft with one 'small' key. OF course,,,, IMHO :D

[Guest]

What's the difference in the heavier rear axle assembly?

[Scott Salmons 7]

Wasn't there also a change in the rear PTO drive shaft? If I am not mistaken the early tractors had a solid shaft while the later used a tubular? Maybe that is what the change in the rear end was.

[JP 0]

Mike, The actual shaft size & bearing, I think 1/8" or 3/16" (been a while since I looked). Scott, Yes, they had two pto shaft assy's. The older one used a carrier bearing & had a solid shaft. :D

[Nigel 0]

Hello to all, thankyou for the detailed replies and your welcome to the club. One of the group gave information earlier when I asked a similar question, but I now have much more detail so thankyou. regards Nigel