How can you adjust a steering wheel?

[Low n slow]

Don't know how this has happened but my steering wheel is half cocked, only slightly but it's really annoying and I've no idea how it happened. It did sit straight, then all of a sudden one day, it didn't.
Any ideas on how I can get it to sit straight again please?

 

[BJ1]

You adjust the wheel position by using the front ball joint on the drag link, right next to the steering box. Basically you jack up the front of the bus, pop out the front joint by taking off the nut and using a proper joint splitter (NOT the fork type), then loosen the nut on the clamp on the threaded part of the drag link arm. By screwing the joint either in or out (effectively shortening or lengthening the drag link) you can adjust the wheel position. But check out all your steering joints first by getting someone in the bus to waggle the steering wheel while you watch the joints. Replace any that are worn before you adjust the wheel position.