From looking at Carl's Cycle parts catolog, it looks like you pull the engine otherwise it would be impossible to undo a nut off of the spinning bolt, by accessing through the boot hole. It usually requires a 1/2" wrench to the bolt shaft beneath the nut, in order to loosen the nut. If the bolt with spherical ball end is not loose, then you just unscrew the tie rod from the entire center assembly, and reattach a new tie rod. Which is also how you remove a bent tie rod, prior to heating and straightening it, should they become bent. One end of the tie rod is reverse threaded.