Case 580CK broken throttle shaft

[etpm]

I have a mid 1970s 580CK. It is the gasoline engine version. The throttle shaft that is in the mess behind the steering column has broken inside the big metal block it passes through. It appears to me that the only way to get this part out to fix it is to remove the gas tank. This is because the uprights for the front bucket arms block the shaft from being pulled out. The shaft will come most of the way out but then it will hit the inside of the upright. Has anybody here replaced this shaft? Right now I have mickey moused a throttle cable because it looks like a two week job to replace the broken shaft and I would really like to get the throttle working as it should.
Thanks,
Eric