Great video on removing stubborn kingpins on HD vehicles.

[someguy]

https://www.youtube.com/watch?v=iNjyy_MPV8k

There won't be as much room to work on a bus, but the concept still applies.   A porta power with a custom frame would do the job.

[chessie4905]

We used to remove kingpins on big trucks with a large brass drift and sledge hammer. GMC Astros used nylon bushings and were easier to replace. If I needed to replace my kingpins, I would pull the axle and take it to a shop that could repair the axle holes if it was necessary. Many times the spindle bores are rebushed and are fine, only to find the kingpin mount in axle is egg shaped. Maybe it is rarely a problem in a coach.

[someguy]

https://www.youtube.com/watch?v=cvR12q9yclE

[Jim Eh.]

Or ... https://www.otctools.com/products/30-ton-king-pin-pusher-set

[someguy]

I already have the porta power.   Time to fab up the rest.